Add a start, stop and pause button to a sage animation

savecancel

Not exactly, but you can try to use 'interact' instead of 'animate'.

http://wiki.sagemath.org/interact/

Also, you can save the animation as a video using matplotlib animation (version 1.1), yet to be updated in sage

http://matplotlib.sourceforge.net/exa...

Or you can save the images from animation as a bunch of images and join them together in to a video using mencoder. Video is more convenient than gif because you can pause it.