Find a driver

TODO: 

- [x] Finish implementation of FindDriver.py
- [x] Create node_taxicab.py for wrapping node_bridge with taxicab paths
- [x] npm install taxicab into sublime-dependents root
- [x] Add "Find driver" to menus
- [x] Add "open all" modifier to menus for find driver
- [x] Document new feature and settings requirements (build_config) in `changelogs` and `readme` and `inital.txt`.

Fixes #25, #90