Fix the last 3 functional test failures:
1. increase the timeout for verifying aggregatestats after uploading and then downloading a package
2. fixed the dotnetcuratedsearchtest by comparing strings all using lower cases
3. fixed the downloadusingNuGetcommandline tests by explicitly specifying the outputdirectory for nuget.exe install
Visual Studio 2012 => Visual Studio 2013
Merge pull request #2109 from robertmuehsig/patch-1

Fixed ReadMe VS Version from 2012 to 2013
Merge pull request #2108 from NuGet/danliu/testfix

Fix the last 3 functional test failures: