Upgrade Nuget package dependencies to 1.8.1 drive

[chrisdrobison]

I'd like to use the Nuget package you have, but we are using the latest MongoDB driver. Please update the package.

[Nanoko]

I just accepted the pending pull requests, sorry I can't reasonably release the package so quick.
You may want to fool nuget by putting a fake one (compiled locally and having higher version number) in the "packages" directory of your solution then upgrade-package.