Several extensions & consolidations.
* Additional Boogie expressions & statements (and_, impl, havoc)
* Rename : SmackInstVisitor -> SmackInstGenerator
* Rename : SmackGenerator -> SmackModuleGenerator
* Handling of phi-node assignments and branching in SmackInstGenerator
* New : handling of LLVM switch instruction
* Removed : limit on variable argument list size
* New : (UNSOUND) ignoring inline assembly calls
* New : (UNSOUND) ignoring unresolvable procedure calls
* New : handling of LLVM select instruction
* New : handling of LLVM PtrToInt expression