mGerrit: make all objects implement Parcelable

To provide for greater portability of objects in the
future we allow quick passing of Objects via Parcelable
implementation.

Fix Gravatars not showing when following a user's actions

Fix AOSP Commit cards not showing

Change-Id: Icf09747be9e58238561a6dfc241c5840b5a54b16
Merge "mGerrit: make all objects implement Parcelable"