Merge pull request #2 from luislavena/support-x64-builds

Support Windows fat 1.8/1.9/2.0 binary builds and x64 builds
Comments and whitespace
Move cross-compilation preparation into win32 script
Remove 1.9.3 win32 binary packaging script
fix typo
Merge pull request #3 from rubys/master

fix typo
Merge https://github.com/larskanis/rake-compiler-dev-box into use-wrappers-for-strip
Use absolute path for strip_wrapper. bootstrap.sh is started with cwd=/home/vagrant