Removed cleaning of reports folders, since this was
interferring with coverage reports generated
sequentially by rake test.

We used to specify specific rake test tasks so that we could run all of
them even if early ones failed. However, that meant that as new tasks
were added, they weren't being run on jenkins.

Now, there is a facility in the rake scripts so that tests can run using
the test_sh function, which will delay failure until the end of the rake
run, unless the TESTS_FAIL_FAST environment variable is set.

Furthermore, this reorganizes the jasmine test tasks so that we can run
those as part of `rake test` as well.

Added comments to tests.rake

to ensure we don't get coverage results from a
previous test run.

Added diff coverage reports using diff-coverage tool.

special case the db setup for the cms acceptance tests. We need the comment client database tables to be created since we're creating the DB from scratch