more case insensitivity
using same exception messages as in esent storage
fixed issues with deleting referenced documents in voron
properly deleting document metadata
Merge branch '2.5-voron' of https://github.com/ppekrol/ravendb into 2.5-voron

Conflicts:
	Raven.Database/Storage/Voron/StorageActions/DocumentsStorageActions.cs
	Raven.Database/Storage/Voron/StorageActions/StalenessStorageActions.cs