Fixed API doc for EventTarget fire method

As per http://yuilibrary.com/projects/yui3/ticket/2532950 the return
value of the fire event was corrected.
Build event-custom-base. Doc changes only.
Merge branch 'live-docs' into dev-master
Merge branch 'dev-master' into dev-3.x

Conflicts:
	build/event-custom-base/event-custom-base-coverage.js