Add tweaked and replaced versions of rbenv's bin, --version, and help commands
Add update command
Add version commands
Add miner-install plugin as submodule
Rename to pick. Get it? You *pick* your *pickaxe*.

...okay, I'll stop now.
Add gitignore
Bump miner-install plugin
Rename pick-version-name to pick-version
Fix pick-versions to stop printing 'current' symlink
Add pick-use to change selected miner
Add pick-exec to run miners
Update pick-help to display additional commands