Major refactoring

Pretty much changed the entire implementation. Fixed some bugs and added some functionality along the way.

Since I introduced some bugs that needed solving, I wasn't able to commit more early. Hence the enormous changset. I will try to keep my commits small in the future.
Merge branch 'master' of https://github.com/bitbored/go-ansicon

Conflicts:
	display/display.go
	readme.md
	windows.go
Updated readme