trying fix GLSL version issue...faild
	new file:   opengl-learning.xcodeproj/project.xcworkspace/xcshareddata/opengl-learning.xccheckout
	modified:   opengl-learning/color.frag
	modified:   opengl-learning/color.vert
	modified:   opengl-learning/main.cpp
	modified:   opengl-learning/textfile.cpp