adds plugin_storage to Player

 this totally un-normalized json string based field can be used by plugins to store information about this player. Kept in a seperate namespace per plugin.
initial commit of new_player_greeter
allows plugins to store abitrary objects
Got everything nice and sorted out. Made a general purposes utility file. Any functions that may be static and can possibly be used for general purposes should probably be migrated here.
Merge branch 'MrMarvin-player_plugin_storage'