Added functions to get cast time of spells and remaining duration of a (de)buff on a target.
Added the empty function for getting the remaining duration of a totem.
Added the function body for RemainingTotemDuration and fixed a couple of comments.
Added documentation of the new API functions.
Merge pull request #31 from emiln/API/5.4-spell-and-buff-functions

A couple of new functions to query spell cast times, remaining duration of (de)buffs, and remaining duration of totems.