first cut PropertyHolder class
all Objects are PropertyHolders
expose fuel property for test
method to add properties to lua table
access properties directly from lua objects
back the property map with a lua table
don't predeclare properties, at least for now
make property map a field, and have one on each body. hackishly teach the lua dispatcher about it
make Body tree inherit PropertiedObject to get its properties, and have LuaObject call out to a per-class properties pusher to get a property table
explicit setter for char*
redo Ship attributes as properties. sucky, but good start