Add appropriate JS docs to the project

Since we have an inflow of new contributors, it is a good idea to describe functions using JS docs to help new contributors. I think [LovefieldService.js](https://github.com/jgraham/wptview/blob/442ae4ff68c61a03c16789d629968ad8b6a8c2fd/LovefieldService.js) is the complicated file and needs to be the starting point.
