Do Not Cache When Response not succesful.
Change projects to framework 4.0 to work in vs2010
Merge remote-tracking branch 'upstream/master' into DoNotCacheWhenRequestNotSucces
When Response is null or Response Not succesful, then do not cache on client or server.
If no content, than no server side caching, but do clientside caching.
Remove null default value.
Merge pull request #14 from rjvdboon/DoNotCacheWhenRequestNotSucces

great, thanks!