GitLab

Added some Gem command shorthands, and ruby shorthand

Add helper function to list gems in a pretty way (only with rvm, for now). Add
missng EOF newline and a todo to the ruby plugin.

Reorganizing plugins so that each plugin has it's own directory now so that any plugin-specific functions can be bundled within there.

Initial implementation of a new plugin system, so that people can managed which aliases/functions they want.