Added first script to find unused files in STK.
Renamed XMLWriter to UTFWriter (which is the correcter name).
Added new player manager, and started to replace the saved data
from user_config with player manager.
Fixed linux compilation.
Removed m_all_players from UserConfigParams (though there are stil
bugs in the new code).
Merge branch 'new_login' of github.com:hiker/stk-code into new_login
Started to move current player info from unlock manager into
player_manager.
Various compilation fixes, some cosmetic changes.
Removed all references to current user/slot from unlock manager.
Removed loading and saving of challenge.xml file.
Made sorting of players descending (instead of using > in operator<),
removed kart and unique id from game slot, replaced some forgotten calls to
unlock_manager with calls to PlayerManager.
Merge remote-tracking branch 'upstream/master' into new_login

Conflicts:
	src/challenges/game_slot.cpp
	src/states_screens/kart_selection.cpp
	src/tracks/track.cpp
Merge remote-tracking branch 'upstream/master' into new_login
Fixed incomplete merge.
Fixed various minor bugs.
Fixed empty user config.xml files.
Added operator<<(const bool&), to get proper true/false written
instead of 0/1 - but it doesn't work yet :(
Removed debug print.
Ignore emacs backup files (*~).
Fixed saving first-time use of the story mode.