Merge pull request #1 from isaacazuelos/commands

Commands
New and Delete commands added.
Fixed the header on `Track.Command.Delete`.

I really need to proofread code before committing.
Merge branch 'commands'
Haddock is content with `Track.Store`.
Updated the Cabal file.
Made `haddock` happy.
Merge branch 'doc'
Added the 'start' command.