Minor improvements

Fix showTiming and slightly improve texture upload
I think webgl is different.  Making this change results in:

    Error: WebGL: texImage2D: format does not match internalformat

From the ES 2.0 spec [1]:

    format
                        Specifies the format of the texel data.  Must match internalformat.                

[1] http://www.khronos.org/opengles/sdk/docs/man/xhtml/glTexImage2D.xml