Switch to using a navigation drawer
Add an action bar subtitle
Update to latest SDK build tools
Make multicolumn view a landscape only feature on all tablets
Add buildStubObject, which builds a small object reference for cases where it is unwarranted to include the full object
Completely overhaul the main feed and object UI mechanisms. Make the UI more modular, enable multiple different "object display types"

IMP-604 IMP-605 IMP-606 #resolve Implemented
PostActivity: Give a default title of Re: the parent post for replies. No longer have a "comment mode" because that's what the comment reply field is for.
Sync 200 activities at a time. This should be quite a bit faster.
IMP-607 #resolve Only copy actor to author when the verb is post
Pull to Refresh
Integrate the Support-v4/v7 libraries in order to get childFragmentManager support on <4.2 devices. This also brings about rudimentary Gingerbread support.