massive cleanup and reorg

* renamed gen files to be lowercase.
* added generators/__init__.py to make it a proper package
* generators now loads individual generators from files
* can now use "from megacosm.generators import NPC"
* removed most Class.Class references (i.e. "MagicItem.MagicItem(app.server, features")
* generators reference siblings via .file import Class (i.e. "from .npc import NPC")