Rewrite for grunt 0.4

I rewrote the main task for grunt 0.4. The plugin is working fine for me now. This should fix issues #1 and #2.

I also added the possibility to specify a base file distinct from the file that the templates should be inlined into (e.g. in my use case, where the base file is `app/index.html` while the templates are actually inlined into `dist/index.html`).