Add decent tracing and overload control to Crest API
Code review updates
Merge pull request #53 from Metaswitch/sto443

[Reviewer Andy] Add decent tracing and overload control to Crest API
Fix exceptions caused by code review updates
Merge pull request #54 from Metaswitch/sto443

[No reviewer required] Fix exceptions caused by code review updates
Merge branch 'dev', remote-tracking branch 'origin' into dev_new_homestead_api