Refactor combo growth

[qqii]

Move combo growth into its own system

[AnthonyWharton]

Why? Combo growth should be handled by the helper functions in the component..

[qqii]

Combo height is in SystemRenderComponent and uses the hasComponent function. It doesn't play well with the rest of the general code from #164.

[AnthonyWharton]

Sorry I have no idea what you're talking about.. What SystemRenderComponent?

[qqii]

I meant SystemRenderSceneNode, which should be more aptly named SystemRenderBillboards.

[AnthonyWharton]

Agree on the rename. So you're talking about the growing size of a player with the combo? This was something that was implemented in the middle of a mid-term demo as an example so it wasn't exactly pretty code.

Again I think this is covered by the, would be nice, but we have lots of deadlines and a report to write.

[qqii]

I think this is needed to prevent floating billboards.