Merged pull request #50

- Merged pull request #50
- Removed exception of adding sample servers to local storage. Sample
servers can be added to local storage like any other server. If they're
not added, the user thinks there's a problem with the application.
- User will have the choice to remove items from the tree and if they
don't want the sample server in the tree, they can remove it.
Resolved conflicts
Merge branch 'pr/50'

* pr/50:
  Working on jsTree events for node hovering
  Completed saving URLs to local storage
  Added localStorage so save REST Services URL
Moved progress bar to page header. Closed #51
Replaced Fancybox with Bootstrap Modal as Container of Popup Maps
Closed #43
Removed fancybox.
Need to add visual indicator that extent preview is loading.
Need to add better error handling for failure to load extent preview.