Feat/minorimprovements

[verybadsoldier]

I would like to propose this PR which includes some improvements (in my opinion):

• when removing directories the retry behavior was changed from try-count based to timeout based. The timeout value can be configured by a property (as a Timespan object). I had problems with the old "timeout" when testing on a machine which was under heavy load.
• some errors that were logged and swallowed before now do throw. In my opinion those errors should be result in failed tests
• changed the name of the MySQL executalbe from mysqld.exe to mysqld_test.exe so it is easy to distinguish from a real mysql daemon