* Added session records to carry resource information over to the
clients
* Added SQL support code for the various views
* Added interface and implementation of the resource information access
component
* Hooked resources information queries into both the empire and planet
management component
* Added resources display to planet and overview pages
* Added structures for resource definitions, natural resources
definitions, resource providers, empire resources and empire mining
settings (both empire-wide and planet-specific).
* Added a few common utility functions to the SQL test suite. These
functions allow test initialisation to be a little shorter.
* Added "MINE" production type and an associated building definition.
The production will not be added to the XML dump or to the output of the
planets summary page, as this is extremely temporary.
