Add rvm-verbose option.
If true, RVM will print various message. If false, it will not print anything.
Add gnu as source in Cask file.
If an error occurs in the callback to rvm-activate-ruby-for, we still want to reset to the old state.
Ruby version support
strip comments from .rvmrc file before parsing version
fixes the following warning: In rvm-run-tests: rvm.el:181:6:Warning: `mapcar' called for effect; use `mapc' or `dolist' instead