Move Gruntfile.js, package.json and .jshintrc too repo root

Summary:
Moving the gruntfile too the repository root.
1. so that I can run `grunt compass` anywhere in the repo.
2. because if we're adding phpspec and other non-ui stuff too our Gruntfile, then it shouldn't live in the UI module

Note: requirejs builds are still broken obviously, working on that.

Test Plan:
- Run grunt compass and see that it still works
- Run grunt jshint and see that it still works

Reviewers: shadowhand

Reviewed By: shadowhand

Differential Revision: https://phabricator.ushahidi.com/D75