DynamicChangelog

Github commit viewer that supports two modes
1) all commits since last update in chronological order *http://gerrit.sudoservers.com/#/c/4542/*
2) select package to view commits in project *api.github.com*
   (allows favorite packages selection)

**fast-forward port from jb branch**

PatchSet 2: rebase
PatchSet 3: use koush's image caching for gravatars
            organize classes
            remove duplicate projects (they only appeared
                afrer the screen was repopulated)
PatchSet 4: fix menu cycling
            fix backstack tracking
            remove unused vars
            code clean up

Change-Id: I7fabaf44562d02f251977a4a5a04ced252768b5e