[12797] Improve handling of SPELL_AURA_EMPATHY

This commit will
* Allow use of Empathy on players (currently incorrect information might still be displayed)
* Fix Empathy such that only the player who cast empathy will get the special information
* Remove Empathy Auras when shapeshifting

See cmangos/issues#531 for details

Signed-off-by: Schmoozerd <schmoozerd@cmangos.net>