Issue #185 - remove commented out code dataSummarization

* The surveyInstance summarization now happens in the surveyInstanceDao, so we avoid double counting when a surveyInstance already exists
Issue #272 - Verify and use the parameter <restApiKey>

* The InstanceConfigurator was not using the key $restApiKey in
  appengine-web.vm
* We enable rest security by default
* We verify that the key is not 'test' nor empty string
Merge branch 'release/1.5.1'
Update release notes with 1.5.1 information
[Cleanup] Remove unused import
Issue #275 - Add apiKey as parameter

* The import process makes API calls to the source instance. This
  requests requires to be authenticated
* We have enabled REST security on _classic_ api
* The process doesn't have a way to know the API key of the source (it
  could be any other instance)
* The user is required to pass the apiKey as GET parameter
Issue #275 - Append apiKey param to the Task builder
Issue #265 - Call invalidate report when deleting a SurveyInstance

* The DELETE method now triggers a `invalidate` message when the user
  deletes a survey instance from the UI
Issue #225 - use Ember.none instead of compare to null
Merge branch 'develop' of https://github.com/akvo/akvo-flow into develop
Issue #275 - Add apiKey as parameter

* The import process makes API calls to the source instance. This
  requests requires to be authenticated
* We have enabled REST security on _classic_ api
* The process doesn't have a way to know the API key of the source (it
  could be any other instance)
* The user is required to pass the apiKey as GET parameter
Issue #275 - Append apiKey param to the Task builder
Added #263 to 1.5.1 release notes
Update RELEASE_NOTES.md
Issue #277 - Changes type from Integer to Long

* The default auto id policy in the Datastore could generate a
  16 digit long number, which triggers a NumberFormatException
  when trying to convert a String to Number
Merge branch 'hotfix-1.5.1.2'
Merge branch 'master' into develop
Merge branch 'develop' into feature/translations