Make the serialization framework compile for system serializers, too. See #1674.
Make the serialization framework compile for system serializers, too. See #1674.

(cherry picked from commit 781744d94f8e8bf1d6d304129646a2a5dcf5df25)

Conflicts:
	data/vibe/data/serialization.d

Fixup.
(cherry picked from commit 54a8150b912ddc31a33a7ce160b9c841d72e94dd)

Fix (de)serialization const-ness mismatch.

(cherry picked from commit 0737075532b53e8e07db3d12034c16dea5fde10d)

Conflicts:
	data/vibe/data/serialization.d

etcimon/vibe.d,rejectedsoftware/vibe.d,Geod24/vibe.d,gedaiu/vibe.d,DBankov/vibe.d,chalucha/vibe.d,etcimon/vibe.d