AT_TARGET should fire during the bubbling phase

Currently when the adjusted node is the same as the target node we invoke a
AT_TARGET event during the capture phase. This leads to issues where the
ordering is confusing.

See https://www.w3.org/Bugs/Public/show_bug.cgi?id=21404 for the spec bug

This fixes issue 68
Merge pull request #80 from arv/at-target-should-be-during-bubble-phase

AT_TARGET should fire during the bubbling phase