* Modified the empire resources update to check for vacation mode and
apply the modifier from vacation.cashDivider if necessary.
* Some parts of the database need to be reloaded:
-> 050-updates/015-empire-resources.sql
* Added a set of tables which define game updates and their targets.
These definitions replace the old enumerate type. Added a set of
triggers which automatically create specific update tables, insert
missing entries, etc... when game update types are being manipulated.
* Removed manual insertion of game updates from empire creation
function and universe generator.
* Added registration of core update targets (i.e. planets and empires),
updated all existing game update processing functions and added type
registrations
* Created Maven project for game updates control components, moved
existing components from the -simple project, rewritten most of what
they contained, added new components for server-side update batch
processing
* Added a new update that computes the amount of resources possessed and
owed by empires. At the moment this computation ignores fleets, as their
upkeep does not use the resource system.
