Add new option `-cleanSimulator` which tells xctool to clean iOS simulator content and settings folder before running every app test run.

It is now possible to tell xctool to clean folder every time before installing test host app. This option sets option `-freshSimulator` automatically.

Sometimes iOS simulator fails to install or uninstall test host app. If that happens we were retrying 3 times before failing, now we are additionally cleaning simulator content and settings folder after each attempt.