Add support for BlackBerry 10 to ExternalScreen plugin

[timwindsor]

Plugin is forked here: https://github.com/blackberry/ExternalScreen

I'd like to investigate adding support for BlackBerry 10 devices to this plugin

[timwindsor]

Resources pulled together by @homynyk :

Here’s a video about using an External Screen with BlackBerry 10:
https://www.youtube.com/watch?v=3xz6YAeKSK0

And the source code:
https://github.com/blackberry/Presentations/tree/master/2013-BlackBerryJam-Europe/JAM321/cascades/src/hdmi

They discuss HDMI 10:05 – 20:30
• There are some bugs in the code so we should be aware of this. I’m not sure it will
be problematic since I believe the bugs are when there are multiple external screens.
• Don't have programmatic control of screen resolutions.

The plugin will require the following functions, (these are just from the client file for the
iOS plugin):
There isn’t much of a description of these functions (nothing in the readme), so I added
what I could find about them.

checkExternalScreenAvailable
//used to determine if an external screen is available
I think the following function can be used for this:
void ScreenFunctions::onTimeout() on line 145 here:
https://github.com/blackberry/Presentations/blob/master/2013-BlackBerryJam-Europe/JAM321/cascades/src/hdmi/ScreenFunctions.cpp
*This is discussed in the video linked to above

loadHTMLResource
// used to load an HTML file in external screen web view. The HTML file can be a local
HTML resource or remote HTML resource but this requires the URL to be white-listed in
PhoneGap.
From what I gathered from the video we will need to render images to the external
screen. I think we can use OpenGL for this:
https://developer.blackberry.com/native/documentation/core/setting_up_basic_opengles_app.html

setupScreenConnectionNotificationHandlers
//used to initialize monitoring of external screen
There will probably be some useful functions for accomplishing this in the link under
checkExternalScreenAvailable.

loadHTML
//used to load a HTML string in external screen web view
This will probably be similar to loadHTMLResource. See above.

invokeJavaScript
//used to invoke javascript, passed as a string, in external screen web view
Some more helpful resources:
The DisplayInfo API will probably be necessary. The documentation can be found here:
https://developer.blackberry.com/native/reference/cascades/bb__device__displayinfo.html#function-attachedchanged-attached

Someone else had a similar idea a while ago. Maybe they can be contacted to see if any
work was done on this.
https://blackberry.icanmakeitbetter.com/nextgen/ideas/externaldisplay?order=vote_count&page=9

[timwindsor]

This plugin does not appear to be posted to cordova.plugins.io or NPM, and on Phonegap-Build it is only used in ~200 apps. It's not likely to be used that much.