Fix monitor/recording for protocolVersion<=15 phones. Reinstate messageStack messages for monitor state. Fix loading monitor state from database. PBX(feature_monitor) returns state of the monitoring state more accurately.

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4989 43c1dc8c-776e-4df2-8ef1-6e829299be21