Fix comparison of elapsed time and threshold in SlowRequestFilter

Fixes #423
Merge pull request #430 from joschi/issue-423-SlowRequestFilter

Fix comparison of elapsed time and threshold in SlowRequestFilter
Fix issue when we specify duration twice.
Merge pull request #435 from alex-bezrodniy/CsvReporterFactory_bugfix

Fix issue when we specify duration twice in CsvReporterFactory.