+mobing contract request signature matching
+mob implemented contract_for
Merge branch 'master' of github.com:thoughtworks/pacto into issue26
Improve the readability of the specs

Contract and ContractRepository now are more clean and easy to
understand ;).
README update [ci_skip]
Merge pull request #26 from thoughtworks/issue26

Pacto request matching (looking up a registered Contract that matches a request signature)