Squashed 'Raven.Voron/' changes from 5d1ad40..d48b105

d48b105 fix for race condition between creating a new transaction, reading tree state and commiting tree state
965635d exposing issue with snapshots that are created during transaction commits

git-subtree-dir: Raven.Voron
git-subtree-split: d48b105851c6f5805f327240056d9eeedbf3f23c
Merge commit '3b97f9bca2c8cc2d9e1044a3bbc4ab1493ae4874' into 2.5-voron

Conflicts:
	Raven.Voron/Voron.Tests/Bugs/Snapshots.cs
	Raven.Voron/Voron/Impl/Transaction.cs
	Raven.Voron/Voron/StorageEnvironment.cs