Missed some !IsNullOrEmpty to convert to IsPresent
Fixed missing check in IsValidKey

- this is a temp hack that should be refactored into something nicer
Generate XML documentation with the Release build
Duplicate TestHelper.DumpSubspace to be able to pass a transaction
First attempt at porting the Vector python layer

- GetRange is not yet implemented
VS 2013 RC insists on adding that to the csproj, not sure what it's about...
Fixed typo in SetReadVersion comment