-added allowed events to 489 errors - thanks to Ionut Slaveanu for this fix

git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@11051 ddefafc4-47db-0310-ae44-fa13212b10f2
-make some RequestContext and Proxy methods virtual to allow overriding

git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@11052 ddefafc4-47db-0310-ae44-fa13212b10f2