rewrite of the Lua module system.
At this time, only E2 is working.
Fixing a lot of old code (monster is no longer id 0).
package.paths configured from eressea.ini
install directory configured from eressea.ini
moving building_action into a seaprate module (it's deprecated)
Merge branch 'master' of https://github.com/eressea/server
Lua module rewrite, part deux.
rules for E3 and E4
some missing files.
removing the core directory (moving to res and scripts).
it's from when open-source Eressea was limited, and we no longer need the separation.
JSON configuration for ship flags.
Use two-phase RESERVE in regular process_orders
deleting the core directory.