This PR contains following changes:
- Give rlgr encode/decode APIs a similar interface
- Make rlgr encode API accessible again
- Make it possible to exchange rlgr functions
- Make use of RLGR1/3 defines instead of 0/1 in decoding
CMake 2.8 does not support default visibility on windows.
To allow building tests add the FREERDP_LOCAL define for each
function that is internal to FreeRDP.
When build with testing these functions are exported and available
for use by tests.
