Build scripts for latest 1.9, 2.0 and 2.1 with rails express patches

Stefan Kaes maintains a set of patches for Ruby: https://github.com/skaes/rvm-patchsets
These add support for memory profiling (most important for development) and various performance enhancements.

Stefan actively maintains these, and has patches for all major versions and many recent patchlevels. I volunteer to maintain rbenv scripts for current and future patchlevels.