Fix bin/box $PWD argument since we may have moved.
Only try to substring match project names not containing a "/".
Add *pwd* check and type hinting to 'find-box.
Decomplect 'all-projects notion from 'resolve-short-proj.
Extract 'safe-delete-repo logic from box-repo-add.

This is in preparation for use in :box-remove.
Add :box-remove functionallity.