Added BuildReadme.md with notes on build script.
Added clean.bat and publish.bat for easy run of Clean or Release target.
NuGet access key is now could be specified as "nugetkey" cmd parameter in publish.bat first or as "nugetAccessKey" variable in build.fsx then, without necessity of manually change script.
Release target depends on All target now.
Clean target cleans packages directory now.
Merge branch 'develop' of https://github.com/tchief/Orchestra into develop