Remove unneeded code
Add file_delete function
Better character_delete LUA function
Introduce context's in_game concept
Remove useless async_send_num
Do not call context_list_mutex outside of context.c
Typo in comments
Do not save user name as long as password is not OK
Add character_out_of_game LUA function

It is not used by any demo yet.
This commit also fixes condition signaling to NPC