make unsink event work correctly in widget

if events were unsunk before a widget was attached
to the dom, event bits would still be sunk, due to
the event bits being cached in sinkEvent() in Widget

fixes ISSUE 7882

Change-Id: If4341e0bf33b4c7b36d55024b3f66fce11ff1ac6
Review-Link: https://gwt-review.googlesource.com/#/c/1950/

Review by: skybrian@google.com
bump pom.xml versions to 2.5.1

Change-Id: I00599828dc2e98ec8d8ff0f6e8d0b2720ac1efbf
Review-Link: https://gwt-review.googlesource.com/#/c/2140/

Review by: skybrian@google.com
Rename RpcSuiteNoBrowser to RpcJreSuite

Change-Id: Iaf2ed6181d1273c304e0122c2fb6a2872c16e2f0
Review-Link: https://gwt-review.googlesource.com/#/c/2141/