Updated NuGet.Core version, to fix problem with file paths containing backslashes from being excluded from package metadata
Fixed NullReferenceException when building projects with no project references

Fixed problem with the output directory not being created when building a project with no project references
Added support for including the version number in the output package file name, for parity with the nuget pack command
Built for version 1.5.0
Merge remote-tracking branch 'origin/master' into AddUnitTests

Conflicts:
	MSBuild/Tasks/NuPrepare.cs
	MSBuild/Tasks/Tasks.csproj
Merge remote-tracking branch 'dtewinkel/AddUnitTests' into AddUnitTests