Aesthetic fix for current-line gutter highlight
Airline: Disabling Powerline Fonts and Updating README
Add various useful commands

* Shell command opens split with results from running command
* * Similar to !<command>
* Find merge conflict search
* Tag files can be placed in .git/tags and will be found at all levels
  of a git repository
* New airline separators
* Allow repeating visual mode commands
* Minor formatting
Workaround fix for vim-gitgutter issue #106

Reference
https://github.com/airblade/vim-gitgutter/issues/106