Added v and fixed j

- `v` Mimics rupa/v: opens the file with vim using viminfo backend.
- fixed `j` alias to only look for directories

[ticket: X]
Changed mkdcd to mcd

`mcd` is much easier (to me, at least) to type and remember than mkdcd
and hasn't (in my experience) gotten in the way of anything else I've
needed to use.

[ticket: X]
Added garrett prompt theme

In working condition but code isn't as clean as I'd like it to be.

[ticket: X]