File Chooser Improvements

I've had limited time today, and I will probably have limited time for a few days in a row here, since I've got a few pressing matters that I need to deal with.

Still, though, I've accomplished a number of things that will be helpful. I've made a number of improvements to the save/load process, including displaying icons for *.forge files, and adding on .forge to the end of filenames of they don't have it already. This way, if you just type in "Junk", it will name the file "Junk.forge". Of course, this has one limitation: if you call the file "Junk.eisqwt", the program will call it "Junk.eisqwt.forge". So ultimately, I'll need to go back and make it so that it only does this if there is not another file extension already.

Below is a screenshot of the current file chooser: