Make sure failed requests do not cause the server to restart.

fixes issue #28
fixes issue #29
fixes issue #31
Fix the error message when a non-200 response is returned.
getSessionContext does not need to be called in createUser because this is taken care of in the wsapi client.
Merge pull request #32 from shane-tomlinson/issue_28_dereference_missing_res

Make sure failed requests do not cause the server to restart.