have an activity module
403 on activity page with disabled activity module

do not allow access to the activity page when of a project
with diabled activity module
do not render links to acticity when it is disabled
hide activity menu item when activity is disabled
hide activity on the overall activity page when it is disabled for a project
have a cuke to test the overall activity page

squash this
fix our good old unit tests
adding specs for the new activity module

add newline at end of file
add CHANGELOG entry for activity module

Conflicts:
	doc/CHANGELOG.md
use stub not stub!

see: http://blog.firsthand.ca/2010/09/rspec-stub-vs-stub.html
refactor event filetering in ActivitiesController

* extract filter code into its own method
* only execute when there is no @project (where @project is set, events are already filtered by sql)