Minor improvements

Fix showTiming and slightly improve texture upload
https://www.opengl.org/sdk/docs/man3/xhtml/glTexImage2D.xml refers to 'table 1, 2 and 3' but fails to include the actual tables.  The red book, 7th edition specifically lists GL_RGBA8 as a valid enum for internalFormat, but on the other hand it's examples simply use GL_RGBA.