Set output paths to build/portable for all portable projects

Consistent paths for .net 2.0, 4.0 and 4.5.
Fix paths nuspec file.
Remove .NET 4.0 target from portable nuget

This is already covered by the portable target for .NET 4.0.
Add .NET 4.5 portable condition to CommonAssemblyInfo template

Also update checked in file to match contents after running a build.

Note: I'm not entirely sure about the impact of these changes,
specifically changing "portable" string to "portable40" and
"portable45". I'd like some review feedback on it.
Delete seemingly obsolete project
Fix whitespace in .nuspec files

Generated by running build-package.bat