This commit extends the original AIY projects
python API to include drivers, APIs and demos
for the AIY Projects Vision Kit.

https://aiyprojects.withgoogle.com/vision/

This lets us do effects, glissandos, phasing, and so on through a nice
and easy python API. Additionally, it adds the toneplayer and
trackplayer classes as well as the tracks to the setup.py script to make
sure they get deployed.

The v1beta1 endpoint has been shut down, so this is necessary for using
the Cloud Speech demo now.

This is a cherry-pick from the voicekit branch.

See google#205.

Summary of changes:
- Fix instructions for using the Voice Kit on Stretch (google#187)
- Make it easier to turn the LED off (google#167)
- Fix crash with trigger sound (google#163)
- Let user code control TTS (google#185)
- Enable hotwording with Cloud Speech (0b4972b)

Restructures for Vision/Voice kit coexistence.

Update to Cloud Speech v1

Restore changes from the voicekit branch

Change-Id: I687ca96e4cf768617fa45d50d68dadffde750b87

Change-Id: I7276ec84ae22adcca3262ad28745302e25bd9a40

Add object_prob_threshold to restrict probabilities, change
max_num_objects default to return all detected objects. Default
behaviour now is to return all detected classes with non-zero
probabilities.

Change-Id: Ibbf97d04dc609bf25c0d5329b7757d1391c9b7cf

Grayscale images are interpreted by VisionBonnet as RGB where all
channels are the same. This is just an optimization to send 3 times less
data over SPI.

Change-Id: I0322cbff8381f295772b1eadead0a4d0d7f335fc

Adds support for Voice V2 and enables the driver for V1.

Change-Id: I5b5c861aca65b6a25e250dbda78535820cbbb969

Change-Id: I33131a033cdf0ffdce9b4ccbe6a67e88aa54cce2

* add immediate option for cloudspeech recognize

* add documentation for immediate argument

The root README.md is documentation for the GitHub repo, shown on the
https://github.com/google/aiyprojects-raspbian. src/README.md is
documentation for the API, which can't contain relative links to files
in the GitHub repo.

Fixes google#214.

This doesn't update from v1alpha1 of the gRPC API to v1alpha2, which is
to follow.

Change-Id: I86a5f2eb73acf51a169ff678af03f24b4d3e1175

Change-Id: Ic51bee63aeb3117f12b6bacfc5452b055b003b7d