[maven-release-plugin] prepare release 2.9.1
[maven-release-plugin] prepare for next development iteration
Updated Jetty to 7.6.16 and 8.1.16.
COMETD-552 - Consistent usage of ServletOutputStream API.

Using ServletOutputStream.print() everywhere.
COMETD-552 - Consistent usage of ServletOutputStream API.
COMETD-539 - CORS requests broken when using jQuery.
Fixed the alternate server URL.
Using jQuery.prop() instead of jQuery.attr().
Merged branch '2.9.x' into 'master'.