Added javadoc to the ModLoader interface.
Added javadoc to the Mod interface.
Added getAvailableMods() implementation to the DirectoryModLoader.
Added updated javadoc to the getAvailableMods() method in the DirectoryModLoader.
Added loadExternal method to ModCollection for loading external mods
Made a method in Retrievers work with the SecurityManager
Merge branch 'issue112-available-mods' of github.com:Cardshifter/Cardshifter into mod-loading
Server now loads all available mods
Checking if directory exists before trying to load mods, to avoid crash
Reduced logging for AI Clients
Added toString method of AvailableModsMessage
Removed game already ended warning, happened when game ended first time
Reduced recource modification logging
Client now shows actual player names instead of 'Player' and 'Opponent'
Made event executing methods for `Component` use generics
Added functionality to eliminate players and give them a win status
Changed game ending to eliminate players
Server sends chat message to inform about who wins a game. Fixes #103
Reorganized a bunch of classes into different packages
Removed API module from test module dependencies