Status line trimming

- Fugitive is awesome, but if I have a long branch name (which is common where I
  work) then it steals all of the real-estate in the status line
- This change turns things like '[Git(feature/XYZ-9999_Description-goes-here)]' into
  something like '{f/XYZ-9999_}'
- Also updated my config for the changes I made to vim-ag