Fix timer leak
Free used constants if not used anymore

Fixes memleak
Fix unitialized value
Close file descriptors used for warnings and messages
Merge pull request #11 from MartinNowack/Memleaks

Patch Set II - Memleaks
Deprecate LLVM 2.8 and lower
Remove stoppoint references
Merge pull request #72 from MartinNowack/deprecate_llvm28

Deprecate LLVM 2.8 and lower and remove support for it
Added support for printing Expr to llvm::raw_ostream

The implementation is a little hacky but is far simpler than changing
all the code to use llvm::raw_ostream instead of std::ostream.

Now we can do things like:

    #include <llvm/Support/Debug.h>
    ...
    ref<Expr> e = /* Some expression */
    DEBUG_WITH_TYPE("klee_something", dbgs() << "Expression:" << e << "\n");