First try at fixing #703.

Adds 'weekly active users exchanging $' message to the top of each page.
Commit forgotten file.
Make the testsuite pass.
Make the case with zero paydays default to 0, 0.
Merge remote-tracking branch 'origin/master'
Fix failing tests after the merge from master.
Fix the fix (sorry).
Update as per comments.
Address also the rounding of the transfer volume.
Merge pull request #1377 from zwn/master

Show number of active weekly users and $ transferred in the headline of each page.