changed RavenDB default unit test storage engine to Voron (default.ps1 script)
Squashed 'Raven.Voron/' changes from 0ee3ef6..f4eccd9

f4eccd9 * added ability to Voron SnapshotReader read/write methods to take into account pending changes in WriteBatch(es) * relevant unit tests

git-subtree-dir: Raven.Voron
git-subtree-split: f4eccd9e87fe769ca68f61b95cd8ec8ed985e15b
Merged into Voron subtree change that allows Voron storage engine when reading/iterating to
take into account pending changes in WriteBatch
Merge commit '40091c4450f95daa7538a5e3599fb61afc520264' into 2.5-voron

Conflicts:
	Raven.Voron/Voron.Tests/Storage/Batches.cs
	Raven.Voron/Voron.Tests/Trees/Iteration.cs
	Raven.Voron/Voron.Tests/Voron.Tests.csproj
	Raven.Voron/Voron/Impl/SnapshotReader.cs
	Raven.Voron/Voron/Impl/WriteBatch.cs
	Raven.Voron/Voron/Trees/Tree.cs
	Raven.Voron/Voron/Trees/TreeIterator.cs
	Raven.Voron/Voron/Voron.csproj
pulled Voron change that allows to take into account when reading/iterating --> pending changes in the WriteBatch
minor fix, changes target framework 4.5 -> 4 and added assembly signing