Expand atomic load to cmp_swp.

LLVM fakes atomic load and store with compare-swap which continues
with original MemoryVT. However, the MemVT should accord with newly
promoted type of arguments. Look like a llvm bug.
Minor fix on making dmg
Update README.md
Update README.md and add overview_of_compiler_stages.md
binutils build on OS X 10.9 fixed
llvm build on OS X 10.9 fixed
Remove cmake-2.8.10.1
Update to cmake 2.8.12
Minor fix for llvm-gcc flag
Minor fix for xcode 5 gcc