First work on reworked sipapp callbacks
Working with sip app callbacks
Changed nksip_sipapp_srv to standard gen_server
Doc updates
route() callback processing
Hack to speed routing processing
Minor change
API in nksip_request and nksip_sipmsg changed
Doc updates
Update metadata.md
New API in callback functions
Updating new API everywhere
New API
Minor bugs
Changed APIs
Merge branch 'sipapp_callbacks' of https://github.com/kalta/nksip_priv into sipapp_callbacks

Conflicts:
	src/nksip_dialog.erl
Doc updates
Tests and samples update
Minor change
Process of single element configs