Fix in free space handling
Properly marking when indexing is in progress. Previously indexing got stuck when exception was thrown during getting docs batch from PrefetchingBehavior
Adding missing assertions to make sure that returned page is really an overflow
Fixing copy/paste bug in the free space handling.
Removing the IExtendedDocumentConversionListener and converting the IDocumentConversionListener to be as functional.
Breaking change
Merge branch 'voron-free-space-issue' of https://github.com/arekais/ravendb