Fixed 'help [<command>]' command

Regex was returning ' <command>' instead of '<command>', therefore preventing the single command help lookup from working.
Added 'Invisible Commands'

Added support for 'Invisible Commands': These commands are commands that have :spec but are not added to :meta. This will allow some commands to not show up in the help results, but still be available for use.
Removed invisible commands from master to move to feature
Merge pull request #7 from TheLarkInn/master

Fix regex for individual command helper.