Get rid of memory leaks.

[Artur K.]

This issue has pretty large footprint, since boomerang was written with garbage collector's help in mind.

I've started working on that on boomerang/leak_be_gone branch .
The plan right now is to use std::shared_ptr/std::uniq_ptr facilities.

@reductor If You have a few minutes, I'd appreciate if You could test this branch on mingw, see if it breaks anything

[James]

@nemerle nicely done, compiles and runs in mingw, should be good to commit

[Artur K.]

Awesome, thank You.