[#664] Check existence of source question before retrieving survey id

* changes made based no review by `@iperdomo`
[#664] Reformatting source code
[#664] Merge branch 'issue/664' of https://github.com/akvo/akvo-flow into issue/664

Conflicts:
	GAE/src/org/waterforpeople/mapping/app/web/SurveyAssemblyServlet.java
[#664] Ignore `sourceSurvey` attribute if there is no `sourceId` in a question
Merge pull request #698 from akvo/issue/664

Issue/664
[#695] Add registrationSurvey attr, if applies

* No attr means regular group
[#695] Use TRUE constant as a comparator
Merge pull request #699 from akvo/issue/695

[#695] Add registrationSurvey attr, if applies
[#690] Merge branch 'develop' into issue/690
[#690] Implements survey publication using S3Util.put