Add jshint task to grunt

Add grunt-contrib-jshint task to grunt and add it to the default task.
Update README.md

Update README.md
WIP Remove all submodule usage

Use node packages instead of git submodules for the developer
dependencies.
Remove old dependencies

Remove jake (since we use grunt now) and uglify-js (since we don't use
that at all).
Remove tilejson from the test suite

The tilejson stuff was never used in the test suite anyways.
Move to the grunt-karma task

Use the grunt-karma task instead of the old hand rolled one.
WIP update to 0.7.1