Squashed 'Raven.Voron/' changes from 01c4616..2b3cfc7

2b3cfc7 fixed an issue with space allocation and items not being added when using PureMemoryPager
c29008b fixed an issue with pager state not being added to transaction when more pages are being allocated

git-subtree-dir: Raven.Voron
git-subtree-split: 2b3cfc743848ab6d265a4a1425b1c53d5671ef78
Merge commit '35ed0e4ff6a583a8c638d06687f6e6bdf6097c20' into 2.5-voron

Conflicts:
	Raven.Voron/Voron/Impl/AbstractPager.cs
	Raven.Voron/Voron/Impl/IVirtualPager.cs
	Raven.Voron/Voron/Impl/MemoryMapPager.cs
	Raven.Voron/Voron/Impl/PureMemoryPager.cs
	Raven.Voron/Voron/Trees/Tree.cs