Merge branch 'hotfix/47'

Close #47
Fixes #46
Merge branch 'develop'

Closes #43
Merge branch 'develop'

Fixes #44 -- allows resource listeners to return `ApiProblem` results, which are
in turn returned immediately by the controller.
Added a section to the readme
Forgot a sentence
Merge pull request #49 from macnibblet/hotfix/document-child-resources

Added a section to the readme for child resources
[#49] Clarified example
Merge branch 'hotfix/49' into develop

Forward port #49