updated aecho

-Now uses config lib for settings
-Settings that are saved across loads are the following: sitrack - sneak/invis tracking, trackalt - send alts messages about buffs/debuffs (these 2 require send addon), buffs being tracked.
-Added toggle for automatic echo drop usage in case you need to stop it from burning through your echo drops.
-Added ability to add/remove buffs from the tracker
-Added ability to list buffs you are watching