[WFCORE-158] Don't allow handlers to be removed if assigned to a logger or another handler.
[WFCORE-159] Don't allow handlers of the same name to be added.
Merge pull request #234 from jamezp/WFCORE-158

[WFCORE-158] Don't allow handlers to be removed if assigned to a logger or another handler.
Merge pull request #235 from jamezp/WFCORE-159

[WFCORE-159] Don't allow handlers of the same name to be added.
Make sure the response has been written before the latch is released
Minor graceful shutdown improvements
Merge pull request #288 from stuartwdouglas/WFCORE-177

WFCORE-177 fix intermittent failure in suspend test case
WFCORE-216 Add ModelValidator to ensure resource model is correct