Add note regarding PATCH requests and HTTP::Server::Simple.

Until HTTP::Server::Simple is updated, PATCH requests will not reach your app
while running in standalone mode; they will, however, work fine under `plackup`
etc.

It seems prudent to me to get support for PATCH requests out there, but make it
clear that, until HTTP::Server::Simple is updated, they will not work in
standalone mode.

lib/Dancer.pm

@@ -1148,6 +1148,15 @@ Defines a route for HTTP B<PATCH> requests to the given URL:
 work as a "partial-PUT", transferring just the changes; please see
 L<http://tools.ietf.org/html/rfc5789|RFC5789> for further details.)
 
+Please be aware that, if you run your app in standalone mode, C<PATCH> requests
+will not reach your app unless you have a new version of L<HTTP::Server::Simple>
+which accepts C<PATCH> as a valid verb.  The current version at time of writing,
+C<0.44>, does not.  A pull request has been submitted to add this support, which
+you can find at:
+
+L<https://github.com/bestpractical/http-server-simple/pull/1>
+
+
 =head2 path
 
 Concatenates multiple paths together, without worrying about the underlying