Upgrade to mocha 1.15.0
package.json: use npm friendly indentation

Closes #10
Update the dev dependencies
Add `save` option which writes the mocha output to a file

Closes #11
Use `this.filesSrc` so that grunt filters can be used

Closes #8
Add a unit test for the `files` option
Rename the gruntfile fixtures
Release version 1.4.0