extract command list to autoload

[toombs-caeman]

Doing this lets people use something like the following in their vimrc:

let g:smoothie_remapped_commands = smoothie#default_commands + smoothie#experimental_commands + [ '{', '}' ]

rather than copying the list of commands in full. This change shouldn't affect anyone with existing configurations.

For parity, the other g:vars could be changed from smoothie_* to smoothie#*, but as it says in the note those aren't really intended to be public.

Also, cheers! It's a cool project

[EriKWDev]

Works great!