Changed to mark the writeable files directory (~/Documents/Hengband previously) with...

Changed to mark the writeable files directory (~/Documents/Hengband previously) with a version number (so it's now ~/Documents/Hengband-2.2.1).  That's to make it harder to load an incompatible save file since the plan is to put out the new Mac OS X interface with the old code base, 1.6.2, and presumably at some point put out a version for the code being called 2.2.2.