Defined "integration.run_tests()" function which can be used to execute
a particular integration test case. Existing bolerplate code in modules
and states tests is replaced with following lines:
if __name__ == '__main__':
from integration import run_tests
run_tests(TestCaseName)
Typical usecase could look like this:
python integration/modules/pip.py --no-clean -vv
Integration tests requiring a salt master and daemon were seperated
from pure unit tests. For now both are run with runtest.py. In
the future it could take arguments for which type of tests to run.
