Added functional tests for /scan* endpoints. See #2.

A minor modification has been made to ``put_scan_control``. See
ticket #54. What remains to be done is actually testing running plugins.
Right now plugins don't start according to output. See #55.
Added /reports* api calls to the tests, but #56 prevents writing tests.

Ticket #56 is blocking me from writing actual tests. It seems like we
have to add users record to either sites or groups. But Stefan will help
me handle this as well tomorrow.