Mobile (+ tablet) support

[EtienneBruines]

We'd like to support engi on Android and iOS.

List of thoughts:

• We would need OpenGL / GLFW available on the mobile device; or refactor a lot
• We would want to support both phones and tablets
• Mobile support should improve in Go 1.6.

Any additional information can be posted in this issue.

Todo list

(will be added upon when needed)

• Add within webgl a compatibility-layer for https://godoc.org/golang.org/x/mobile/gl
• Add within engo, w.r.t. the OpenWindow, RunIteration, runLoop functions, a compatibility-layer for https://godoc.org/golang.org/x/mobile/app (Compare https://github.com/EngoEngine/engo/blob/gopherjs/engo_netgo.go with https://github.com/EngoEngine/engo/blob/gopherjs/engo_glfw.go for a general idea on what's needed,

[matiwinnetou]

+1 killer feature and would make engi professional not a toy project. Games on mobile are a reality since companies and individuals can earn serious money with this.

[paked]

@matiwinnetou would you be interested in heading up this development?

[matiwinnetou]

@paked no this is at the moment too big for what I can afford to this project. :(

[lovoror]

Great!

[EtienneBruines]

See #274 - done.

[paked]

🎉