Merge pull request #29 from whitequark/master

Loosen ffi dependency
Bump version.
Improve support library configuration Rakefile.
Update the support library for LLVM 3.3.
Update FFI bindings for LLVM 3.3.
Rake is a runtime dependency required for compiling support library.
Migrate to minitest 5.
Use bundler to simplify Rakefile and weed out strange test bugs.