Update VS 2013 - remove hardwired libzmq ref and default to nuget.
Merge branch 'zeromq/master'
Add missing dependency, clean up VS soln file, fix bool expression.
Update projects to pull updated nuget package id.
Merge pull request #420 from evoskuil/master

Update VS 2013 projects, remove hardwired libzmq ref and default to NuGet.