Tests for composer

Built on top of #28.

PLEASE, DO NOT MERGE UNTIL #28 IS MERGED.

- https://trello.com/c/ObThuTMy/1755-proper-testsuite-for-api-blueprint-api-app
- https://trello.com/c/CuPDy6Ve/1739-api-blueprint-api-error-handling-proper-http-codes
Don't do this, please.
Javascript cannot offer you assurance when cycling through object-key-value hash - especially when it goes about the "key-value" order.

Please define the defaultFormat by hand - as it **is** an expected value, you as author really expect.