Fxied plugin initialization. Added build script via gulp. Added MIT license.

This PR fixes the plugin initialization. Previous implementation caused errors if the 'disable' method was called before the plugin has been initialized. Now multiple instances of the plugin can be enabled/disabled.

I've also added a gulp build script. To run it: 
npm install
gulp

You need to install node.js for this.

I've taken the liberty to rearrange the directory structure. I find it more legible and it helps for both the build via gulp and the deployment via bower.

There was no license. I've taken the liberty to add the MIT license. You remain free to choose whichever other license you want, of course.

The bower config is set to use the "jPulse" name. Would you mind registering this plugin at bower.io after you've updated it?