Expandable list for pivotal stories
Enhances pivotal tracker integration by letting user select project. A
lot of structural enhancements to support further expansion of
functionality.

Signed-off-by: Johannes Westlund <iceman@westlundarna.se>
Merge branch 'ExpandableList' into pivotalUS

Conflicts:
	app/AndroidManifest.xml
Bugfix. Fixes issue with crash on click of pivotal-tracker-stories
Sorts stories of selected project by current_state in an expandable
listview. Offers checkbox for further integration of
follow-functionality.
Merge branch 'pivotalUS' into development

Conflicts:
	app/src/se/chalmers/agile5/activities/PivotalActivity.java
	app/src/se/chalmers/agile5/activities/UserStoriesActivity.java