Generate an GL_INVALID_VALUE error when user calls glGetXXX() with a null out pointer instead of crashing. Fix glGetIntegerv of GL_SHADER_BINARY_FORMATS to not write anything out to the provided buffer.
Fix glGetIntegerv(GL_SHADER_BINARY_FORMATS) to not write anything to the out pointer, since the output array is empty.
Merge pull request #1835 from juj/gl_get_null

glGetXXX fixes.