[NaCl SDK] AppEngine: update smoothlife, improve UI

* The new smoothlife allows for float value scaling
* Select box for thread count
* Select box for simulation size
* Slider for zoom
* Make the buttons thinner and put them on one line (makes the page less
  long)

BUG=none
R=sbc@chromium.org

Review URL: https://codereview.chromium.org/68013002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234236 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234236