ofTrueTypeFont: fix spacing, kerning, hinting and clean code. Closes #2787
Fix for parsing a string of format "r,g,b,a" (without comma's). This adds proper support for the XML standard.
Added ofDirectory canRead/Write/Execute functions. Fixed #1669
ofGLReadyCallback() updated

Updated ofGLReadyCallback() to fix crash on check for GLSL version when the OpenGL context version is < 2.0.
Update to ofGLReadyCallback()

Changed ofGLReadyCallback() to check for null pointer of GLSL version string instead of checking OpenGL version and proceeding from there.
emscripten port
compile.core.mk: fix core clean target
add emscripten makefile config
addons .gitignore for emscripten
Merge branch 'master' into feature-emscripten
Merge branch 'master' into feature-emscripten
emscripten: html5video gray format was incorrect
emscripten video: faster RGBA->gray conversion
emscripten video: faster conversion RGBA->gray
emscripten video: faster RGBA->grayscale
Merge branch 'master' into feature-emscripten
emscripten: use same timming calls as in linux
emscripten: URL file loader implementation
emscripten: alert and text dialogs
ofTrueTypeFont: Compute initial lineHeight using font metrics instead of a guess