Revert "Implement ArraySerializer and move old serialization API to a new namespace."
Revert "Implement ArraySerializer and move old serialization API to a new namespace."

This reverts commit 8896b4fdc8a543157cdf4dfc378607ebf6c10ab0.

Conflicts:

	activemodel/lib/active_model.rb
	activemodel/lib/active_model/serializable.rb
	activemodel/lib/active_model/serializer.rb
	activemodel/test/cases/serializer_test.rb

SweeD/activeresource,eileencodes/activeresource,om-nishu-trantor/activeresource,yui-knk/activeresource,chadzilla2080/activeresource,1776/activeresource,rjordan/activeresource,rails/activeresource,Shopify/activeresource,maclover7/activeresource,repinel/activeresource,wyattisimo/activeresource,delameko/activeresource,peterjm/activeresource