Changes to allow compilation in Ubuntu Quantal 12.10 32 bits and new "Transparent Background" and glass "Max internal reflection bounces"

As discussed with povmaniaco, I have done the Pull Request against the experimental branch for the new parameters.

While trying to compile the experimental branch in Ubuntu 12.10 Quantal 32 bits, I had several problems that broke the compilation. I have also included here the fixes I put there, I hope they help and they don't cause problems.