Reverted some changes from #786 that shouldn't have been committed.
Made it possible for the nightly builder to handle prerelease suffixes in nuget versions. For example 4.0.0-alpha.
Fixed path to nunit.exe to be nunit3-console.exe so that it now works. I think eventually we want to use tools like this in a more clean way (without having to commit files like these to source control, depend on hardcoded paths, locally installed tools etc) but thats something for #718
Projects in tools now use net framework 4.7.2 instead of 4.5.2 so that this is now consistent with all other net framework projects.