Bfexec

Changelog:

1. Optimized some sections of the code. There is a minor performance boost of about 10% in some large programs.

Changelog:

1. Add multiply loop optimization support. Now the interpreter is on average x1.5 to x2 faster compared to the previous release!

Changelog:

1. Fix a bug that was preventing the compiler from optimizing Brainf\*\*ck code, that was given to it.