modules/ims_usrloc_scscf: New features to fully support subscription to reg_event
	Main change add API to presence module library to store the callid/totag/fromtag presentity combination
	Also only remove IMPU from usrloc if there are no subscriptions to it
modules/ims_registrar_scscf: lookup.c - fixed term_impu_registered to work for tel URI as well as SIP URI
modules/ims_registrar_scscf: New features to fully support subscription to reg_event
	Main change to support PUBLISH of reg event information
	And to use new usrloc API storage of callid/totag/fromtag presentity combination to correctly process usbsequent SUBSCRIBE
modules/ims_registrar_pcscf: New features to support P-CSCF subscription and publishing reg event
	Migrated pua_reginfo functionality to ims_registrar_pcscf so ims_usrloc_pcscf is used
	New features include subscribing to reg event on Registration, processing notifications and publishing when reg event changes
modules/ims_qos: Changed Rx event processor child from PROC_NOCHLDINIT to PROC_SIPINIT
examples/pcscf and scscf: Changed config file to use new P-CSCF subscription and publish reg event