BETA: `L2Object` update.
	* Renaming ˙isAttackable˙ -> `canBeAttacked`.
	* Renaming `isL2Attackable` -> `isAttackable`.
	* Adding JavaDocs.

git-svn-id: http://svn.l2jserver.com/branches/unstable/L2J_Server_BETA@6367 d34dfa0f-f91c-0410-86dd-cf06f19dd0ad