Cache control

Enable or disable cache and specify validity of cached data. Usage of cache is controlled in context of routing by CONNECT too. Removing stale cache file can be done periodically using CRON.

--	----------	------------------	----------------------------------
	CACHE	do|no|ro	control to do cache or not
*	EXPIRE	days|hours|secs	expiration of the cached data
	CACHEFILE	fileNameSpec	in which file cache data are stored
*	ICP	icpClientConfig	configuration as an ICP client