Add abstract controller unit tests and translations

[mkly]

Changes proposed in this pull request:

• Add unit tests for controller abstract-delete-controller
• Add dependency(devDependency) for ember-sinon-qunit for use in
  stubbing methods for proper test coverage
• Update documentation with @todo about possible unintended behavior
  of the sortByKey action
  The tests in this commit preserve the behavior as implemented. It is
  possible that sortByKey should also set nextStartKey and startKey
  to null as well.
• Add translations for _notifyReportError in
  abstract-report-controller
• Add unit test for _notifyReportError
• Add translations for _setReportTitle in abstract-report-controller
• Add unit tests for _setReportTitle with translations
• Add unit tests for abstract-report-controller
• Add unit tests from abstract-paged-controller

Finally needed the sinon devDependency here. I'll circle back after this is merged and pull the timekeeper stuff out.

Not 100% sure of where I should be putting the translations in the locale file. Just making a best guess so definitely let me know if I should move them to a better spot.

This is all in one big PR because of later tests needing sinon as well. I tried to keep the commits clean, so when reviewing it is probably easiest for you to step through the commit diffs if you are looking to get a closer look at the changes.

cc @HospitalRun/core-maintainers

[jkleinsc]

Thanks for the PR @mkly! Looks good to me.
I think the translation locations are fine, but that file needs some more organization (eg we are not always using a consistent hierarchy), but I don't think that should be cleaned up as part of this PR.

In regards to nextStartKey and firstKey that looks like a bug to me, because those values could potentially change on sort.