WowAce

Archarodim:
    - Added more information to the assert()'s message of last commit.
    - Added an assertion to diagnose another Lua error which might be related to the one fix in the commit before last.
    - - The API UnitSetRole() has become protected in 5.2 so delay its call until the player is no longer in combat. - cleanup
    - Fix a Lua error happening is some conditions when several nameplates share the same name and one belongs to a detected healer. This error let HHTD in a wrong state which could translate into healer symbols not being properly hidden and thus appearing randomly on non-healer nameplates...