More work on Planet List

The planets' economy system is nearly done.  Planet List screen is almost done as well.  The only remaining features is to implement infusing a planet with reserves to boost its production, and the dialog for it.

After those are done, I will re-do the Fleet Design List window and implement Fleet List screen.  As well as bugfixes and minor tweaks.  At that point, I will upload a new version to Desura.

Here's a screenshot of my progress, note the new taskbar at bottom.