Upgrade to VS2012 & use NuGet for Azure Storage Client dependency

Hi. I had cause to use your Azure Sorage upload task today, but I had problem with dependencies (which I've fixed): Your code was using an old version of the Azure Storage Client assembly, which I couldn't find. I've updated the project to use NuGet to pull in the 1.7 version of the library.

There is a bit of a [Wall of Pink] (http://www.hanselman.com/blog/YoureJustAnotherCarriageReturnLineFeedInTheWall.aspx) thing going on here, I'm afraid, because in the first of the two commits I followed GitHub for Windows' advice and added a .gitattributes (and .gitignore) file. I'm happy to split the pull request, if you prefer.

Thanks,

James Chaldecott

P.S. This is my first ever Pull Request, so go easy on me! :-)