Use step timing for cursor blink to save CPU rendering
Use step timing for cursor blink to save CPU rendering

The blinking cursor used the default timing function for its transition,
which caused Chrome 29 on OS X to take 100% when the Marathon tab was in
the background. The default timing function eased between 0- and 1
opacity, which ate CPU to composite on each step of the animation.

Switching to a step function means there are only two steps: opacity 0
and opacity 1. The composite time required is a tiny fraction of before
with a Chrome background tab taking <2% CPU, possibly due only to normal
activity and not the animation.

This also more closely mimics a real terminal; cursors typically blink
instead of fade.

This StackOverflow question pointed me in the right direction:
http://stackoverflow.com/a/13293044/368697

quamilek/marathon-ui,Raffo/marathon-ui,mesosphere/marathon-ui,watonyweng/marathon-ui,yp-engineering/marathon-ui,watonyweng/marathon-ui,janisz/marathon-ui,pierlo-upitup/marathon-ui,cribalik/marathon-ui,cribalik/marathon-ui,yp-engineering/marathon-ui,pierlo-upitup/marathon-ui,quamilek/marathon-ui,Raffo/marathon-ui,mesosphere/marathon-ui,Kosta-Github/marathon-ui,janisz/marathon-ui,Kosta-Github/marathon-ui