The archive tables and the map
------------------------------

The aim of the archive tables is to reduce the amount of data which needs
to be stored in InnoDB tables, which are transaction safe but don't perform
perfectly on Dreamhost, and have a very large index size:data size ratio.

Data in the archive tables is used to either: Return a game to a previous 
state, to enable generating statistics, or more usually to allow maps from
any game and any turn to be drawn whenever required.
 

The orders from the *previous* phases are the ones which the map draws, and
so the map will always get the orders to be drawn from the archive, and 
not from the active orders table.

At the end of every phase Orders, TerrStatus, and Units are placed in the 
archive. TerrStatus and Units will delete any conflicting records from a 
previous phase in the same turn, while Orders doesn't have conflicts and
so can be written without problem.

During the Diplomacy phase the previous turn is still drawn; only after the
Diplomacy phase is a fresh map with newly processed Diplomacy orders rendered.

e.g. In turn 0 the map seen is not the map created at the end. The map during
the Diplomacy phase displays the outcome of the previous turn, and so the map
for a given turn is not a map of what happened during that turn, but a map of
what things looked like *at the start* of that turn.