MOTECH-628: Migrated Commcare to MDS

Commcare now uses MDS for storing application schemas.
Couch dependency was dropped.
Some duplicating classes were dropped, since json field
naming conflicts are no longer an issue - applications
are not stored as json documents.
Also done some minor cleaning up.

Change-Id: I8bbd92103b8f5b5af7b375e217290c7343c21846
Merge branch 'master' into dev/commcare-mds

Merging with the version pushed to gerrit.
Branch can be considered dead now.

Conflicts:
	modules/commcare/src/main/java/org/motechproject/commcare/domain/CommcareApplicationJson.java
	modules/commcare/src/main/java/org/motechproject/commcare/domain/CommcareModuleJson.java
	modules/commcare/src/main/java/org/motechproject/commcare/domain/FormSchemaJson.java
	modules/commcare/src/main/java/org/motechproject/commcare/domain/FormSchemaQuestionJson.java
	modules/commcare/src/main/java/org/motechproject/commcare/domain/FormSchemaQuestionOptionJson.java
	modules/commcare/src/main/java/org/motechproject/commcare/service/CommcareApplicationDataService.java
	modules/commcare/src/test/java/org/motechproject/commcare/service/impl/CommcareAppStructureServiceImplTest.java

Change-Id: I65a83f42dee2b734f7722b90b00e2ecf84102654