MapList storage in memory.txt

The more I work on MapChoices, the more I realize that the classic map list format is insufficient
for what we need.

As I post this, the current memory structure is this flatish structure:

ArrayList of all maps
|- mapdata_t mapData
	|- char[] map
	|- char[] group
	|- StringMap mapAttributes
		|- char[] value
	|- StringMap groupAttributes
		|- char[] value
	
groupdata_t also exists, but solely as a transfer medium.

The obvious flaw in this model is that the group and groupAttributes are stored with the map itself.
This makes it a mess to get a list of unique groups, as well as parsing group attributes.

I've considered a few new formats.  The first was this:

StringMap of all groups
|- Arraylist
	|- mapdata_t
		|- char[] map
		|- char[] group
		|- StringMap mapAttributes
			|- char[] value
		|- StringMap groupAttributes
			|- char[] value

This fixes the group, but the groupAttributes are still off there in lala-land.

So, that brings up a third version:

StringMap of all groups
|- groupdata_t
	|- char[] group
	|- StringMap groupAttributes
		|- char[] value
	|- StringMap maps
		|- mapdata_t
			|- char[] map
			|- char[] group
			|- StringMap mapAttributes
				|- char[] value

I originally considered an ArrayList at the maps level, but this makes it more difficult to pull up
the mapAttributes given a map name.

This version changes groupdata_t to a first class citizen.

You now need to drill down farther to access the information you want.  This format also makes cleanup
more complex. However, it also makes it considerably easier to pull up group information.

I think some helper methods could be used to make this structure easier to use.

Note that the group string is still in mapdata_t, as these are often passed to methods that need the mapdata
and group name.

Note: We're intentionally not using KeyValues, so don't suggest them.