Grid Chart Work

I'm still working on Grid Chart, although I'm taking a couple of college courses which slows the pace. The two main areas I've been working on are error handling and user settings. A big improvement I got in is that images used for sims (for instance elevation maps) are now created on a background thread, so that the user can continue to use the map as they're loaded. I also added some more events generated by the map control. At the moment there are: SimSelectionChanged, SimUnderMouseChanged, and SimFocusChanged. There are a number of planned features that I'm putting off until I get this initial version done.

Here's a pic of what the main Grid Chart window looks like today, with color elevation maps in the middle of loading.