Filters should be responder instances.
Move content filter to a filter.

Remove static variable from SaveResponder.
Code cleanup in wiki importer code.
Fix exception when suite is run without test pages.
Move the actual importing logic for WikiImportingResponder to WIkiImportingTraverser
Move ImportError to traverser class.
Remove TestEventListener and all related code.

Imports are triggered explicitly from the TestResponder. This removes that last static field. We can make FitNesse really modular now.
Fix title on import page.
Remove virtual page css.
Rename WikiPageProperties.isImported to isImportedSubWiki.

Fix wiki import for imported root pages.
Merge pull request #386 from amolenaar/import-traverser

Improve modularity of wiki responder module