Test multiple configuration sets
Get rid of unnecessary spaces in muc_SUITE
Run test specification couple of times

Running test spec couple of times instead of using {repeat, N} allows to
label each configuration run with it's name
Use error_logger:info_msg/2 instead of ct:print/2 before tests start
Update README
Add more detailed configuration test information
Add quicktest make rule

This rule runs tests omitting configurations given in test.config file.
Merge pull request #29 from esl/jenkins_squashed

Test multiple configuration sets