* 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
* Changed the way mining settings work: use a priority value (between 0
and 4) as the weight. Leaving them as they were before would have caused
numerous problems (and a lot of unnecessary code to work around them)
* Empire mining settings will be created along with the empire's own
record. By default all natural resources will have weight = 2.
* Added a set of four stored procedures which can be used to update an
empire's mining settings, including planet-specific settings. The
emp.mset_update_start() function can be used to start an update (on an
empire's settings if there is only one parameter, or on a planet's
settings if there are two parameters); the emp.mset_update_set() and
emp.mset_update_apply() functions are then used to modify the settings
and apply the changes, respectively.
