Do not fail if YARD coverage increased
Merge pull request #102 from tarcieri/improve/do-not-fail-if-yard-coverage-increased

Do not fail if YARD coverage increased
Extract Headers::Mixin into separate file
Implement new Headers class
Fix Headers usage in request/response
Refactor request/response Headers related specs
Fix Headers#inspect on Ruby 1.8.7
Fix Headers#to_h spec
Merge pull request #92 from tarcieri/feature/improve-headers

Refactor headers
Remove obsolete BodyDelegator
Bump up YARDStick threshold
Merge pull request #104 from tarcieri/cleanup/remove-obsolete-body-delegator

Remove BodyDelegator
Make HTTP::Headers Enumerable

Closes https://github.com/tarcieri/http/issues/105.
Do not override user specified Host header
Merge pull request #106 from tarcieri/refacor/dont-enforce-host-header

Do not override user specified Host header
Add Headers#empty?

Closes #107
Rename Headers#from_hash to Headers#coerce
Allow coerce Headers from #to_a
Fix YARDstick threshold
Workaround Ruby 1.8.7 any object responds to to_a