#269 Add brokered assemblies to samples dependencies folder.
#269 Ensure brokered proxy/host assemblies are copied to samples folder.
#271 Update version numbers for 4.5.581 prerelease
#271 Update nuget definitions for prerelease
#271 Update setup version for 4.5.581 prerelease
Merge pull request #272 from rockfordlhotka/master

Version 4.5.581 prerelease