Fix an issue we investigated for a customer, where the database took too much time to respond due to thread starvation. What happened is that we had too much threads waiting to the database to be initialized, so we run out of threads to actually initialize the database. Now we do limit just for the first 5 threads asking to initialize a database, and returning 503 once we reach that limit.
Avoiding global max 5 concurrent runs.
Only limit concurrent requests to 5 pending to load.
fixed test
fixing EsentTempPathInUseException exception in RavenDB-560 and RavenDB-993 tests
Making sure that we'll only keep faulted items in the resource store cache if they are currently being disposed
Merge pull request #576 from ayende/2.5

Updates