(feat) Added FromIterator impl to StackChain

You can now easily collect into StackChains from arbitrary iterators of
`Box<Middleware>`. This makes creating StackChains of middleware dynamically
extremely easy and makes inserting 'conditional' middleware much easier.
(fix) Specified types for nightly break.
(fix) Updated Makefile dependencies.
(feat) Updated Makefile for cargo.
(feat) Updated Travis.
Merge pull request #74 from iron/fix/new-target

(fix) Update the Makefile for Cargo compatibility.
Merge pull request #73 from reem/feat/collect-to-chain

(feat) Added FromIterator bound to Chain