Enable ability to set orientation

[djipco]

Here is a little proposal: it would be really cool if we could force the orientation used by the camera (portrait or landscape). Currently, there does not seem to be a way to do that.

By the way, I tried doing it with cordova-plugin-screen-orientation but, even though the reported orientation changes, the behaviour of CanvasCameraPlugin does not.

I guess the most logical way would be for CanvasCameraPlugin to simply follow window.screen.orientation. This way it would allow us to set it through the screen orientation plugin (or other) without adding bloat to CanvasCameraPlugin.

Thanks for your work on this plugin!