Added doublePendulum.gif to README.md.
Reduced duration of simulation in README.md. Also reduced dimensions of doublePendulum.gif; now <1Mb.
Merge branch 'master' of https://github.com/simbody/simbody into readmeGIF
Changed doublePendulum.gif path to relative.
Removed superfluous brackets around link.
Merge pull request #146 from tkuchida/readmeGIF

Added doublePendulum.gif to README.md.

Thanks, Tom!