FLOW OF STATE  (What is forbidden at each step)

#include
makeMap()
A:		Load map file
B:		Pass map data
C:		Draw new map


- A: Load map file -
Request map XML
* prevent changing chipset during load
Wait for map to load, then...
Request chipset image files
Wait for all requested chipset images, then...
draw map
* allow changing chipset during load

- B: Pass map data -
Request chipset image files
* prevent changing chipset during load
Wait for all requested chipset images, then...
draw map
* allow changing chipset during load

- C: Draw new map (layer, chipset) -
* prevent drawing, until 1+ layers  &  1+ chipsets
Create layer
Request a chipset image file
* prevent changing chipset during load
Wait for all requested chipset images, then...
* allow changing chipset
* allow drawing

- C: Draw new map (chipset, layer) -
* prevent drawing, until 1+ layers  &  1+ chipsets
Request a chipset image file
* prevent changing chipset during load
Wait for all requested chipset images, then...
* allow changing chipset
Create layer
* allow drawing