Add loadbalancing tests
Multiple cluster support

Conflicts:
	tests/integration/__init__.py
decommission and bootstrap ccm commands
Spotted small bug in random test
Remove try/except blocks and use use_*dc() instead
Increase wait_for_down. Replace log messages.
Grab futures before counting coordinators
Remove double future.result()
Confirm stacktrace
Use execute_concurrent
Merge branch 'master' into load_balancing_tests_master
Cleaned up and re-tested test cases
Merge pull request #105 from joaquincasares/load_balancing_tests_master

Load balancing tests (against master)