(fix) Temporary hack for travis.
(refactor) Changed Ingot to Middleware.
(refactor) Updated example to use Middleware.
Merge pull request #47 from zzmp/refactor/ingot-to-middleware

(refactor) Change Ingot to Middleware.
(doc) Updated Alloy for Middleware.
(doc) Updated Furnace for Middleware.
(doc) Updated Iron for Middleware.
(doc) Updated Middleware for Middleware.
(doc) Updated README for Middleware.
Merge pull request #48 from zzmp/doc/ingot-to-middleware

(doc) Change Ingot to Middleware.
(feat) Added SendFile trait to Response.