Option to automatically save after each turn

If enabled, automatically saves to Autosave.xml in the program's
directory every time you click the next turn button.  Handy if your
computer crashes, or you forget to save the player's current HP and such
at the end of the evening.
Merge branch 'autosave' of git://github.com/grantemsley/DnD4eCM into grantemsley-autosave

Conflicts:
	bin/Release/DnD4e Combat Manager.exe
	bin/Release/DnD4e Combat Manager.pdb