Camera Open test

Adds a base for the camera test.
I've setup the basic canvas functions while mcasas@ did the pixel checking logic.

The pixel checking logic needs some tweaking as I've noticed it does not always detect near black pixels.

More is planned as noted in the TODO list in the top of the camtest.js file.

Creating this pull request from a clean branch due to messing up the previous pull request in terms of commits etc.
Instead of having a CamCaptureTest namespace with methods and variables inside, I think it is better if you have a proper CamCaptureTest class:

function CamCaptureTest() {
  this.isMuted = false;
  this.stream = ...
  this ...
}

CamCaptureTest.prototype = {
  run: function () {
    doGetUserMedia( , this.gotStream.bind(this));
    ...
  },

  gotStream: ...
};


addTestSuite("CamCaptureTest", 
function () {
  var test = new CamCaptureTest();
  test.run();
});