Pick module to perform action on.

This allows a user to pick the module he wishes to perform the action on.
It eliminates the hassle of looking up the exact module name and appending it to the command.

```` bash
modman update
1) typo-sensitive-modulename
2) another-typo-sensitive-modulename
Please specify the module you want to update:
````

It should not interfere with other options and will only be triggered on relevant commands (update|deploy|remove)