fix reduce timer for log...
should be started before call to MapReduce.GetItemsToReduce
When we have a very large number of document references and there is a put, pulse the transaction so we would avoid esent out of memory errors.
We don't backup temporary indexes
optimize GetItemsToReduce

does not request keys - that have already been processed for a specific level
Fixed conflict
RavenDB-903 Intersection queries with searches fail when out of order
Merge branch 'master' of https://github.com/steinho/ravendb
Simplifying the API by introducing a params class
Changing reduceKeysDone to be hash set instead of list
Making sure that esent & munin behaviors are the same
More refactoring to make it easier to follow