Fix compilation error
Fix a failing test. When we do HEAD request for the static endpoint, we need to return the Content-Length with the attachment size.
Fix the failing test, where the Version of the next generated was null
minor
Fix typo
Better assertion
Merge commit '37a44849be04cacf9b5fa3506e7e0bc4d7cff05f' into New3

Conflicts:
	Raven.Voron/Voron/Impl/TransactionMergingWriter.cs
Merge commit '71006f0b7e6200d03ad3b7659aec140596fe7ff6' into New3

Conflicts:
	Raven.Voron/Voron/ValueReader.cs
Merge branch 'New3' of github.com:ayende/ravendb into New3

Conflicts:
	Raven.Voron/Voron/ValueReader.cs