For a TimedItem with infinte duration, the transformed time should should be equal to the directed time

Currently, in order to calculate the transformed time from the directed time,
we divide by the duration to get the time fraction, apply the timing function,
then multiply the result by the duration. This means that if the duration is
infinity, the transformed time is always zero, so the TimedItem's effect or
children will not play.

For a group, this behavior is probably unexpected. Consider the following
example ...

document.timeline.play(new ParGroup([
  new Animation(foo, bar, {iterations: Infinity, duration: 2}),
  new Animation(foo, bar, {iterations: Infinity, duration: 3}),
]));

A reasonable expectation is that both animations will repeat inefinitely, but
currently, neither will play. Note that in this example, the
'iterations: Infinity' can't easily be moved to the ParGroup because the
animations have different durations.

Instead, if the duration is infinity, we should set the transformed time to the
directed time. This means that the childrens' inherited times will progress as
expected, so they will play.

Note that the time fraction will remain zero, so an Animation with infinite
duration will still not play.
Add touch demo
Merge pull request #483 from dstockwell/touch

Add touch demo
Add a demo that animates SVG paths
Remove junk from test
Merge pull request #484 from steveblock/pathEffect

Add a demo that animates SVG paths
Merge pull request #485 from steveblock/cleanUp

Remove some junk
Ensure that auto-test-compositor is testing x values for x-value animation.
Merge pull request #486 from shans/fixTest

Ensure that auto-test-compositor is testing x values for x-value animati...
add initial version of index page
add initial version of index page
add initial version of index page
initial demo landing page
add the zeppelin
refactor demo directory
Revert "refactor demo directory"

This reverts commit 4454f3c9fc7241a188d4d0f046cf5088d5929e01.
add viewport tag
add viewport height
better responsive design
even better responsive design