Add v4.0.19 release notes
Rearrange img labels
Merge pull request #915 from e-kolpakov/master

RequiresAnyRoleAttribute.HasAnyRoles made virtual
minor word fixes
Update release-notes.md
Add filtering support in metadata pages
Only search on the first field
Update README
Pass EmulateHttpViaPost to PclExport.CreateWebRequest()
Update img resources to point to Assets repo
Don't attempt to set CookieContainer
Always emulate requests when client.EmulateHttpViaPost=true
Only force EmulateHttpViaPost for SL5 clients, then use actual req.Method to send request body

Also ensure ContentLength still sent for null requests (i.e.
ContentLength = 0).
Grr, ContentLength not supported in PCL, fallback to publishing a 0 byte request stream to signal ContentLength
Update SL5 .xap