Fix some typos in CONTRIBUTING.md (#422)

CONTRIBUTING.md

@@ -8,7 +8,7 @@ Use your best judgement, and feel free to propose changes to this document in a
 ### raylib philosophy
 
  - raylib is a tool to LEARN videogames programming, every single function in raylib should be a tutorial on itself.
- - raylib is SIMPLE and EASY-TO-USE, I tried to keep it compact with a small set of functions, if a function is too complex or has not a clear usefulness, better not to include it.
+ - raylib is SIMPLE and EASY-TO-USE, I tried to keep it compact with a small set of functions, if a function is too complex or is not clearly useful, better not to include it.
  - raylib is open source and free; educators and institutions can use this tool to TEACH videogames programming completely by free.
  - raylib is collaborative; contribution of tutorials / code-examples / bugs-solving / code-comments are highly appreciated.
  - raylib's license (and its external libs respective licenses) allow using it for commercial products.
@@ -23,6 +23,18 @@ Use your best judgement, and feel free to propose changes to this document in a
 [raylib Wiki](https://github.com/raysan5/raylib/wiki) contains some information about the library and is open to anyone for edit. 
 Feel free to review it if required, just take care not to break anything.
 
+### raylib C coding conventions
+
+Despite being written in C, raylib does not follow the standard Hungarian notation for C, 
+it [follows Pascal-case/camel-case notation](https://github.com/raysan5/raylib/wiki/raylib-coding-conventions), 
+more common on C# language. All code formatting decisions have been carefully taken
+to make it easier for students to read, write and understand code. 
+
+Source code is extensively commented for that purpose, raylib primary learning method is:
+
+ > learn by reading code and examples
+
+
 ### Using raylib develop branch
 
 raylib [master branch](https://github.com/raysan5/raylib) contains latest raylib release but all 
@@ -36,21 +48,9 @@ use provided [Makefile](https://github.com/raysan5/raylib/blob/develop/src/Makef
 
 For detailed information on building raylib and examples, please check [raylib Wiki](https://github.com/raysan5/raylib/wiki).
 
-### raylib C coding conventions
-
-Despite being written in C, raylib does not follow the standard hungarian notation for C, 
-it [follows Pascal-case/camel-case notation](https://github.com/raysan5/raylib/wiki/raylib-coding-conventions), 
-more common on C# language. All code formatting decisions have been carefully taken
-to make it easier for students to read, write and understand code. 
-
-Source code is extensively commented for that pourpose, raylib primary learning method is:
-
- > learn by reading code and examples
-
-
 ### Opening new Issues
 
-To open new issue for raylib (bug, enhacement, discussion...), just try to follow this rules:
+To open new issue for raylib (bug, enhacement, discussion...), just try to follow these rules:
 
  - Make sure the issue has not already been reported before by searching on GitHub under Issues.
  - If you're unable to find an open issue addressing the problem, open a new one. Be sure to include a 
@@ -62,16 +62,16 @@ To open new issue for raylib (bug, enhacement, discussion...), just try to follo
 
 ### Sending a Pull-Request
 
-To send a pull-request, first of all, make sure you're sending it to **develop-branch**. Here are some other rules:
+To send a pull-request, first of all, make sure you're sending it to [develop branch](https://github.com/raysan5/raylib/tree/develop). Here are some other rules:
 
- - Make sure thee PR description clearly describes the problem and solution. Include the relevant issue number if applicable.
+ - Make sure the PR description clearly describes the problem and solution. Include the relevant issue number if applicable.
  - Don't send big pull-requests (lots of changelists), they are difficult to review. It's better to send small pull-request, one at a time.
  - Verify that changes don't break the build (at least on Windows platform). As many platforms where you can test it, the better, but don't worry
  if you cannot test all the platforms.
 
 ### raylib bindings
 
-Some people ported raylib to other languages in form of bindings or wrappers to the library, here it is a list with the ones I'm aware:
+Some people ported raylib to other languages in form of bindings or wrappers to the library, here is a list with the ones I'm aware of:
 
  - [raylib C/C++ version (default)](https://github.com/raysan5/raylib)
  - [raylib Lua binding](https://github.com/raysan5/raylib-lua)
@@ -83,12 +83,12 @@ Some people ported raylib to other languages in form of bindings or wrappers to
  
 Usually, raylib bindings follow the convention: `raylib-{language}`
 
-Let me know if you're writting a new binding for raylib, I will list it here and I usually 
+Let me know if you're writing a new binding for raylib, I will list it here and I usually 
 provide the icon/logo for that new language binding.
 
-### contact information
+### Contact information
 
-If you have any doubt, don't hessitate to [contact me](mailto:ray@raylib.com)!.
+If you have any doubt, don't hesitate to [contact me](mailto:ray@raylib.com)!.
 You can write me a direct mail but you can also contact me on the following networks:
 
  - [raylib forum](http://forum.raylib.com/) - A good place for discussions or to ask for help.
@@ -100,8 +100,8 @@ Thank you very much for your time! :)
 
 ----
 
-Here it is a list of raylib contributors, this people has invested part of their time 
+Here is a list of raylib contributors, these people have invested part of their time 
-contributing (in some way or another) to make raylib project better. Huge thanks to all of them!
+contributing (in some way or another) to make the raylib project better. Huge thanks to all of them!
 
  - [Zopokx](https://github.com/Zopokx) for testing the web.
  - [Elendow](http://www.elendow.com) for testing and helping on web development.