Previously I packed standard library variable arguments as well as
file operation into one define `NK_INCLUDE_STANDARD_IO`. This caused
some problems and I split the define into two. So if you want the old
behavior you need to define `NK_INCLUDE_STANDARD_IO` as well as
`NK_INCLUDE_STANDARD_VARARGS`. If you only want file operations but
not variable arguments only define `NK_INCLUDE_STANDARD_IO` and
if you only want varargs but not file operations please only define
`NK_INCLUDE_STANDARD_VARARGS`.
I had a long standing bug inside nuklear which prevents you from
swapping out a font while the code is being build. This bug is now
fixed but the fix requires _ALL_ `nk_user_font` data structures
provided by `nk_style_set_font` to be persistent.
All platform and renderbackend independent examples are now optional
demos for all platforms in `demo/`. Moving some demos from `example/`
provides an easier way to test GUI concepts for users and simplifies
maintenance.
