Compile ruby in separate directories for each architecture.
Headers and tests added

The build script now generates headers as well as the library. In
addition, an Xcode project that tests the embedded ruby runtime on iOS
devices/simulator.
Load ruby standard library into bundle

The ruby standard library is now included in the bundle.
Fixed gitignore mistake in previous commit
Add instructions for using the library

Describe how to properly use the library.
Merge branch 'develop'