Improved Refreshing Algorithm and Fixed Spark Posting Bug

Refreshing algorithm now improved. Instead of destroying all of the loaded Jawns and fetching the most recent from the database, the app continually fetches the most recent Jawns until it finds one that matches the first Jawn in the gridview. This way, the ones that are loaded are kept and simply have their indices shifted.

This new refreshing function now is called after loading Jawns from cache on startup.

Also fixed the Spark posting bug, which disallowed Sparks with any tags from being posted.

Date formatting is also included in there somewhere as well. I'd like the explore the PrettyTime library in depth sometime though.