Update protocol messages (AccessoryStatusMessage, MediaPathCapabilityMessage, StimulusMessage, XMLAlarmMessage). Updated SKINNY_BUTTONTYPE, SKINNY_STIMULUS, SCCP_FEATURE enums.

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5124 43c1dc8c-776e-4df2-8ef1-6e829299be21