Update README.md

Fix incorrect  pod spec
Adjust the regexp so that we can handle extra sub versions.
Add missing project argument to gcloud commands
Rename util.config.Watcher -> util.config.Broadcaster.

Watch is a widely used term in the codebase, which doesn't capture
the key feature of this type: broadcasting a change to several
listeners.
Rename watch.Mux -> watch.Broadcaster

A few reasons:
- Mux is already widely used in the codebase to refer to a http handler mux.
- Original meaning of Mux was something which sent a chose one of several inputs to
  and output.  This sends one output to all outputs.  Broadcast captures that idea
  better.
- Aligns with similar class config.Broadcaster (see #2747)
Typo in header
Merge pull request #2748 from erictune/clean7

Rename watch.Mux -> watch.Broadcaster
Merge pull request #2747 from erictune/cleanup6

Rename util.config.Watcher -> util.config.Broadcaster.
Merge pull request #2731 from brendandburns/bash

Adjust the regexp so that we can handle extra sub versions.
Merge pull request #2626 from jasonkuhrt/patch-1

Fix incorrect pod spec in tutorial
Merge pull request #2755 from MikeJeffrey/awstypo

Typo in header
Merge pull request #2753 from MikeJeffrey/kubectl

Use kubectl in getting started guide
Merge pull request #2730 from satnam6502/scripting

Add missing project argument to gcloud commands