update supertest to 0.13.0
tests: exclude untestable lines in examples from coverage
tests: add more acceptance tests
tests: add accepts test with params
tests: add param test with encoded value

closes #2143
Include ETag in HEAD requests

backport of commit 3c7310ebcbee1d65f47e6c6115ade2fa4cbd5b59
update connect to 2.18.0
update send to 0.4.0

closes #2150
deps: should@~4.0.0
mark res.send ETag as weak and reduce collisions
deps: update example dependencies
tests: add more etag tests
improve etag control for res.send

closes #1435
closes #2129
tests: add more tests
3.9.0
Merge tag '3.9.0'