Cleaned up more systems for general includes

Graphics systems and windowing system bridges had the same glew and wxglew glexew headers duplicated a couple times over, that was really unnecessary, idk why I didn't think to make a general include for them when I did that. Also made general includes for collision systems although there was only one header that could be put in there. Also merged together common widget system headers, and fixed a bug with GTK not having show_error defined, added a little //TODO: statement with it.