Test keyword classify captured audio

[dophanngoc]

the model supports capturing streaming voice data from on-board microphone then detecting keyword, In order to adapt with the application requirement and proof on concept. it needs have capabitily of loading local sound files as input instead.

[google-cla[bot]]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

For more information, open the CLA check for this pull request.