Add support for listing partial matches

[roubles]

With this commit, you can list bashmarks that start with a certain text, by passing that text to the list command. For example:

$ l
drill2             /Users/roubles/drill2
drillfoo           /Users/roubles/drillbar
drillbar           /Users/roubles/drillfoo
frontend           /Users/roubles/git/paging-alfred-2017-03-28/src/main/frontend
git                /Users/roubles/git

and now, if I want to list only the bashmarks that start with drill:

$ l drill
drill2             /Users/roubles/drill2
drillfoo           /Users/roubles/drillbar
drillbar           /Users/roubles/drillfoo

Also, the list function now supports tab completion to show the best matching bashmark.