Fix blank responses for store with synchronous ops

fixes #61
1.6.4
Do not require req.originalUrl

closes #57
tests: change the majority of the tests to not use express
deps: istanbul@0.2.16
Move req.cookies warning after validating signature

fixes #62
would-be maintainers: use your own initiative!
deps: debug@1.0.3
deps: istanbul@0.3.0
deps: express@~4.5.0
1.6.5
deps: express@~4.6.1
deps: debug@1.0.4
deps: depd@0.4.2
Improve session-ending error handling

closes #66
1.7.0
deps: mocha@~1.21.0
deps: depd@0.4.3
1.7.1
deps: depd@0.4.4