Merge pull request #32 from ldesplat/master

Upgrade to Hapi 4.x
version
Fix #34: check for state error onPreResponse.

If hapi detects a problem with state, e.g. if cookie decryption fails,
the onPreAuth handler will be skipped and request.session will remain
unset. Check if the session exists before handling it.
Merge pull request #36 from reid/check-state-error

Fix #34: check for state error onPreResponse.
Update package.json
Hapi 6
test cases support Hapi 6. Breaking change
Remaining test upgraded to Hapi 6
Merge branch 'master' of https://github.com/ldesplat/yar
Rebasing with official repository