Have Syntastic ignore angular attribute warnings

The Syntastic HTML linter will warn on propriety attributes. The
likelihood that you *accidentally* typed "ng-repeat" is low. Let's just
assume you know what you're doing and ignore warnings about "ng-*"
attributes.
Remove test:prepare from migrate alias

* `rake db:test:prepare` has been depreciated in rails 4.1
Remove Zeus and Cucumber references

* Spring is now built in to Rails:
  http://weblog.rubyonrails.org/2014/4/8/Rails-4-1/
* Haven't used Cucumber on a project in over a year
tat: create tmux session if nonexistent
Add Shift+Tab map for tab complete in insert mode

Feature parity with `<c-p>` `<c-n>` tab completion duo.