Reduce the default max items to index (and to keep in memory for indexing) to 16K in 32 bits.
Allow to override GetHolder, so users can create more sophisticated replication strategies.
Take into account the type when using OrderBy on lucene
Record the latest etag _before_ doing filtering
Making sure that we take into account the etag of system documents, so we don't have to skip them.
Will remember the latest status etag and skip it as well
Making sure that we aren't stopped by spans of documents that aren't replicable