Hapi v17 Compatibility Release

[gugwad]

• [x] Updated the plugin to be fully compatible with async/wait.

• [x] Used hapi master(now 17 version) branch for linking and testing.

• [x] Upgraded code and lab version to 5 and 15 above respectively. This helped in transitioning all the test cases to async/wait compatible.

• [x] Bumped major version number to 2.0.0

• [x] Changed documentation and example code

Tested for hapi 17.1.1 application node version 8.9.1 npm version 5.5.1

[gugwad]

Applied for review comments. Please check @timcosta