Update a2po, remove unused scripts
Rebrand as Tasks

* Change package to org.tasks
* Replace 'Astrid' with 'Tasks' in string files
* Replace icons
* Remove no_activity_container
* Remove unused drawables
Sign APK with Gradle
Merge branch 'master' into dropbox

Conflicts:
	astrid/src/main/java/com/todoroo/astrid/activity/EditPreferences.java
	astrid/src/main/java/com/todoroo/astrid/activity/TaskListActivity.java