Fixed GET attribute by valueID
Fixed PUT attribute by valueID
Fixed AppendContextElementRequest parsing in JSON
Added tests for GET, PUT and DELETE Attribute Value Instance
Merge branch 'develop' into bug/convop_metadatas
Fix in copyright notice
CHANGES_NEXT_RELEASE updated
Merge branch 'develop' into bug/convop_metadatas

Conflicts:
	CHANGES_NEXT_RELEASE
Test harness updated with StatusCode responses where apropiate
Register entity -> Create entity, to conform to current terminology
ADD fixme comment
Merge pull request #282 from telefonicaid/bug/convop_metadatas

Bug/convop metadatas