Input Subsystem Enhancements

[jonbonazza]

Over the last couple of years, there has been several discussions over the current issues with the current Input subsystem design. There have been a couple of high level proposals on the topic that have been made, but nothing has really been fleshed out.

Since Input is one of the foundations of a game engine, I think it's time that we start considering the future of Engo's input subsystem, taking lessons learned both from this project, as well as from the industry as a whole, and apply them to a new and improved input subsystem.

This issue is to act as a discussion forum of sorts, where we can open the floor for people to propose designs and showcased prototypes for feedback from the community before landing on a consensus on what the actual implementation should look like.

Related issues:

• Touch system in common  #540
• Input Abstractions` #433
• Joystick/Controller Support #221

I'll continue to update this post as each subtask is completed. This ticket is more for tracking and discussion purposes rather than an issue in and of itself.

@Noofbiz we should be careful to update this issue any time any more input-related issues come up that can be done in a backwards compatible way. Also, if discussions in this issue lead to any new ideas, we should create new issues for each of them and update this issue appropriately.