Hapi 8 support

[franciscogouveia]

The changes I've made are stable now for a hapi 8 release. Refactored also the testserver.js file with hapi 8 code.

To test it:

node tests/testserver.js

When the limit is reached, the following response is given (as expected):

{"statusCode":429,"error":"Too Many Requests","message":"Rate limit exceeded"}

Note: might be not backward compatible with older versions of hapi.

[cl-aaron]

Awesome Thank!