Add OpenFL game engine

[flashultra]

OpenFL is cross platform development engine supporting compilation to iOS , Android , HTML5 and other platforms

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Editing an existing topic or collection

I'm suggesting these edits to an existing topic or collection:

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OpenFL started as a replacement for the popular Flash API, but following the open source path.
Now it supports many platforms like HTML5, Android, iOS.

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Something that does not neatly fit into the binary options above

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