OF-937: OFMeet plugin should define J2EE web-app version in web.xml files

OF-937: OFMeet plugin should define J2EE web-app version in web.xml

OF-936: Plugins build task should fail on error by default.

OF-930 & OF-935 Fixes

OF-930: When a directory is defined by property, that should be used instead of a relative reference.

OF-934: Shared configuration for the Ant javac task should be predefined

Address XSS issues in admin console and monitoring plugin (master)

A number of stored XSS issues were found by Dean Hardcastle during testing of
the monitoring plugin's admin console. These include cases where chatroom
nicknames and message text are not adequately escaped.

OF-933: Initial WebSocket implementation

Allow users to specifiy custom classes to map credentials from certificates

OF-631: Fix upgrade script for SQLServer

Determine whether optional stream management is available, fallback to
standard routing; allows WebSocket plugin to be installed for versions
3.10.0 and greater (per plugin.xml)

Adds websocket capabilities compliant with the latest specifications
(RFC 7395).

Note that the new component is implemented as a plugin, but I have
included a few small modifications to core classes to improve
extensibility.

I have tested these changes using the stanza.io client library on both
Chrome and Firefox.

Fixed small copy paste error in hybrid auth provider

FIX: Monitoring plugin list request with max tag does not work correctly

OF-631: Implement SCRAM support

Initial xep-0198 message ack implementation

OF-903: Simplify backup packet delivery

Original issue (OF-857) has been addressed by providing an alternate
packet deliverer (to offline storage). This additional logic was an
ill-advised "belt-and-suspenders" attempt to prevent the recursion which
was occurring before the backup deliverer was implemented.

After discussion with Jonny, switched the existing Map to a Deque, and in
response to Tom's suggestion, added XEP-0203 (and legacy) delay stamping.

Tested using Gajim and Swift; testing the delay stamping was done by disabling
the acknowledgement handling to force retransmission.

This patch adds a basic, non-resumable, XEP-0198 acking solution. It will
redirect "lost" messages to offline storage, but does not attempt to suspend
the session, so will not allow any resumptions.