XUnit add separate block for all tests failed at setUpClass

Plugin NoseId now also adds failed-to-setup-test-suite tests to .noseid file.

• Add 'lode_runner.plugins.Suppressor' plugin. Allows suppress any exceptions in tearDown-methods

• Add optional parameter '--xunit-dump-suite-output'. If enabled drops TestSuite-level sysout/syserr to XUnit report.

• Add plugin ClassSkipper fixing nosetests skip for TestClasses - now skip setUpClass too.
• Fix StopIteration during xml merge
• XUnit plugin now prints full path to generated report file

Add Plugin Failer
Plugin allows to stop test execution after X failures/errors met: provide --fail-limit X argument

Merge pull request #24 from vkorostelev/add_more_dataproviders_options

Add more dataproviders options