Previously every texture that was flagged for NP2 fixup used a vec2
uniform in the shader to store texture dimensions.  Turns out that the
GLSL compilers just maps vec2 to vec4, so essentially wasting 2
floats. The new code only uses vec4 uniforms but packs dimensions info
of 2 textures into a single uniform.

In case lastActiveRenderTarget is destroyed.

Discussed with Juan Lang, We could look for the signinfo at the 
beginning of the cab and restore the file pointer afterward.

This allows IE7 to read the signing information from downloaded ActiveX 
controls.