significant updates to the way item level documents are handled

Significant updates here to how an item is handled. Removed functionality of downloads #59 and table inspection #60 but created feature tickets for them. Left old js plugin in for reference but map-view.js should be removed when those tickets are completed.

Now a geoblacklight application can be configured to it's host institution using the rails_config gem. This settings file should be automatically created at config/settings.yml when the generator is run.
Make sure to use `var _this = this;` or you are inadvertently using a global `_this`. Although in these cases it's probably not even necessary to locally scope `this`.