Turned suite run directory into a rolling archive.

Re-running a suite will not overwrite existing log files.
Just warn if site or user config parsing fails.

If the site config file is broken it will not prevent users from running
suites if the cylc defaults or their user config file is sufficient.
Disable by default, and warn about Rose compat.
Replaced sys.exit with raise exception.
loadleveler job name: prefix with suite name.
Merge pull request #454 from hjoliver/relax-site-user-config

Just warn if site or user config parsing fails.
Merge pull request #457 from matthewrmshin/llsubmit.suite.task

loadleveler job name: prefix with suite name.
Nicer error message.
Make test-battery command compatible with previous change.
Merge pull request #455 from arjclark/db-rogue-exit

rundb: replace sys.exit()
Merge pull request #453 from hjoliver/run-dir-rolling-archive

Turned suite run directory into a rolling archive.
cylc.job_submission.loadleveler: fix import.
cylc run: support "now" as a start tag.
Merge pull request #458 from matthewrmshin/loadleveler.fix

cylc.job_submission.loadleveler: fix import.
In the test-battery, poll before wait.

This gets the result from each test as it comes in without blocking on
the long-running suites.
test-battery: don't print run dir location.
Two test suites inadvertantly using 'at' scheduler

and would therefore fail if atd was not running.
test-battery: validation failure should be a test failure.
Checked all test suite tasks run as fast as possible.
A simple wait-and-retry loop for the name registration DB.

This only matters if you attempt to register several suites at the same
time, which one test suite now does.