(feat) Converted Furnace to Chain.
(feat) Converted StackFurnace to StackChain.
(feat) Converted Iron to use Chain.
(feat) Changed exports to work with Chain.
(feat) Implemented Middleware for Box<Chain>
(feat) Converted examples to use link.
(doc) Brought README up to date for Chain.
(doc) Changed smelt to link.
(doc) Changed from Furnace to Chain.
Merge pull request #62 from reem/feat/chain

(refactor) Converted from Furnace to Chain.