[BUGFIX] Fixed NPE in TempPotionEffect, Task #40 Error - Bloodbending, Task #23 NPE - IceSpike Error - Combustion

* TempPotionEffect - Error: http://www.projectkorra.com/threads/errorstacks-cause-pastebin-deletes.361/#post-3086
** Fixed NPE
* Bloodbending - Error: http://www.projectkorra.com/threads/errorstacks-cause-pastebin-deletes.361/#post-3087
** Fixed error in bloodbending where targetentity somehow is in a
different world (probably by command) and that ends up causing errors
* IceSpike - Error: http://www.projectkorra.com/threads/errorstacks-cause-pastebin-deletes.361/#post-3089
** Caused by not checking if removed timers contains players
* Combustion - Error: http://www.projectkorra.com/threads/errorstacks-cause-pastebin-deletes.361/#post-3090
** Fixed error in combustion regarding removeAroundAPoint() with a location from a different world