Update to NLog v3.0.0.0
Update package restore method

Fixes [#5](https://github.com/uhaciogullari/NLog.Interface/issues/5).
See
[here](http://blog.davidebbo.com/2014/01/the-right-way-to-restore-nuget-packages.html)
for more details.
Updated package and assembly versions
Merge branch 'kfrancis-master'