Merge pull request #37 from ehiggs/master

Issue #34 Pypi package does not include "tools" directory
Add PassManagerBuilder.loop_vectorize property
Update README for LLVM 3.2.
Make cbuilder optimizations optional
Begin to expose Pass class.
Add auto detect PTX/NVPTX support and disable them in the C-extension.
Adding target specific passes.
Add simpler API for building pass-managers given a TargetMachine.
Add test to verify new pass APIs and loop-vectorizer.
Fix exception syntax for Py3
Add clone method to TargetData.
Add optional TargetMachine param to EngineBuilder.create.
Introduce finalizer module to manage finalization of C resources.
Add CodeModel
Wrap LLVMGetPointerToGlobal & add ExecutionEngine.get_pointer_to_global.
Fix breakage of LLVM 3.1.
Add LLVM version number in llvmpy.
Add test for ExecutionEngine.get_pointer_to_global
Add ExecutionEngine.add_global_mapping
Updated names of passes
Suppress warning for missing loop-vectorizer feature if user is not enabling it.