Add -O switch and add SLPVectorizer/BasicAliasAnalysis under it.
Change pass order to more closely match Clang's.
Add patch to LLVM 3.3 with enhancements for vectorizing tuples.
The patch contains functionality and tests backported from
SLPVectorizer changes added to LLVM 3.5.0.
Merge branch 'adr/slpvector' of https://github.com/ArchRobison/julia into adr/slpvector

Conflicts:
	src/codegen.cpp