Added ActivityModel for the comments

Change-Id: I6049f4a0b982b901e8de1754482a650138137cad
Added Activity Presenter, Observer. Changed fields in Model. Waiting for
GUI stuff, ActivityView is just there for compiling, will be replaced by Beard Alex's stuff later

Change-Id: Idc89f8761a5f39542546a1a9ced5141bd0b7de49
okay i squashed 5 commits. they should all be the same thing... not really
sure.
Add requirement manager to build.gradle

Added ActivityModel for the comments
Change-Id: I809fa040b5bb06a8feefc97c6659f0b8599f39e0
fix merge conflicts .
Will's updated TestActivityEntityManager for real this time

Change-Id: I4538fa9b00714e5e8c71d62011e4a5711d6d7d9c
Fixed ActivityObserver comments

Change-Id: Idd0e3baa19e54476a4230e32df72d9f256f45f3c
Merge branch 'feature/comments' into dev with fixed comments

Change-Id: I20795164631ad62e10006c73b88998c92d7be2cf