Removed reference to Cactus from documentation

Issue: SPR-11280
Merge pull request #435 from snicoll/SPR-11280

* SPR-11280:
  Removed reference to Cactus from documentation
Improve the "contributing documentation" readme

Update the "contributing documentation" readme to include the correct
gradle goal and provide a troubleshooting section.
Hard-wrap CONTRIBUTING-DOCUMENTATION at 90 chars
Merge pull request #434 from snicoll/ascidoc-liveupdate

* ascidoc-liveupdate:
  Hard-wrap CONTRIBUTING-DOCUMENTATION at 90 chars
  Improve the "contributing documentation" readme
Fix various documentation issues

- Remove formatting that interferes with code highlighting
- Fix some XML syntax issues
- Added missing punctuation
Merge pull request #429 from VasylTretiakov/master

* pull429:
  Fix various documentation issues
Add minor optimization to AbstractErrors

Issue: SPR-11304
Add method for HTTP PATCH in MockMvcRequestBuilders

Issue: SPR-11299

This is short to avoid having to use MockMvcRequestBuilders.request()
and instead have a simple patch(url, params...)
Removed TestGroup.LONG_RUNNING marker from Groovy and JRuby tests
Fixed resolveProxyTargetClass exception message
Added compatibility note on WildFly 8
Replaced reflection code with straight Servlet 3.0 setAsyncStarted call
Polishing
Fall back on user in the Jetty UpgradeRequest

The Jetty ServletWebUpgradeRequest implements getUserPrincipal to
return the Principal from the HttpServletRequest on the upgrade.
This change ensures we can fall back on that.

However the JettyRequestUpgradeStrategy still passes the user from
HttpServletRequest from the upgrade, in order to work with Jetty
9.0.x and avoid running into this 9.1.x issue:

https://bugs.eclipse.org/bugs/show_bug.cgi?id=423118
Allow hook to associate user with WebSocket session

This change adds a protected method to DefaultHandshakeHandler to
determine the user for the WebSocket session. By default it's
implemeted to obtain it from the request.

Issue: SPR-11228
CronTriggerFactoryBean allows 'calendarName' and 'description' to be specified

Also making 'description' available on SimpleTriggerFactoryBean.

Issue: SPR-9771
(cherry picked from commit 7502ecd)
Polishing
Recognize Content-Type as special header in MHSRB

When adding headers generically, MockHttpServletRequestBuilder now
recognizes Content-Type and updates the contentType field accordingly.

Issue: SPR-11308
Stop using deprecated junit.framework.Assert class