requestor: free from server APIs

except tcp-handler in the module internals
requestor: moved I/O + net to libknot, moved requestor
common: moved strlcpy & sockaddr to common
sockaddr: changed parameter to ambiguous sockaddr for type check
requestor: prefixed with knot_
libknot: A/AAAA address getter
utils: moved endian.h based stuff to private implementation

endian.h checks for config.h define, which isn't available when
the header is exported.
common: print.h moved to common
rr/aaaa: cleanup
requestor: generate query from processor if not provided
mm: mm_alloc/mm_free replaces direct use
requestor: support for UDP proto
net: missing udp_recv_msg
processing: mm is pointer, updated api, tests
overlay: implemented process layering

overlay allows multiple processes to be chained to each other as
a processing pipeline
Merge branch 'master' into resolver_compat

Conflicts:
	Knot.files
	src/knot/nameserver/update.c
	src/knot/nameserver/update.h
	src/knot/server/tcp-handler.c
	src/knot/zone/events.c
	src/knot/zone/zone.c
	src/knot/zone/zone.h
	src/libknot/packet/net.c
	src/libknot/rdataset.c
	src/utils/nsupdate/nsupdate_params.h
Merge branch 'master' into resolver_compat

Conflicts:
	src/libknot/packet/net.c
Merge branch 'master' into resolver_compat

Conflicts:
	Knot.files
	src/knot/nameserver/update.c
	src/knot/nameserver/update.h
	src/knot/server/tcp-handler.c
	src/knot/zone/events.c
	src/knot/zone/zone.c
	src/knot/zone/zone.h
	src/libknot/packet/net.c
	src/libknot/rdataset.c
	src/utils/nsupdate/nsupdate_params.h
pkt: reset sections on packet clear
processing: split layer/process APIs

layer - implements FSM on prepared packets
process - implements FSM on raw wire (uses layer)