Update jQuery.maskedinput to use GruntJS instead of Jake

[codeimpossible]

The grunt build will automatically pick up new spec files and executes via the command line. You'll need to install the grunt-cli npm package globally to run the grunt build:

$ [sudo] npm install -g grunt-cli

Then just install the npm packages specified in the package.json and run the grunt build.

$ npm install
$ grunt

Some further questions/thoughts:

• do we care about generating the distribution copies on the default build task? Should we use a separate task (release?) to do this?
• the grunt file reads the package description and version from the package.json, if we merge Bower support #105 we should change this to take the values from component.json and only use package.json for build dependencies.