Partially removed global *db-cache-path* (might need to add it back for performance reasons, used in rmt: calls.)
Modified common:get-db-tmp-area to get info from dbstruct instead of globals.
Added proc to open area dbs
Gutted dboard:areas-update-tree. Does only areas now.
First pass on some refactoring in db:get-db, db:open-db, db:dbfile-path (these need to be reduced to one function).