Start of CZML clock work.
Merge branch 'master' into czmlClock
Merge branch 'master' into czmlClock
Add DynamicClock object and specs.

I'm not thrilled, but it gets the job done.
Add doc and fix a few typos.
Merge branch 'master' into czmlClock
Workaround issue #602

The current implementation of SceneTransitioner is fundamentally broken. It only accounts for primitives that exist at the time the transition starts. Since the visualizers add primitives on demand, the Polyline for orbits drawn in Earth/Fixed does not get added until the first frame after the transition begins. Therefore, the visualization is incorrect until the transition completes.

The short term easy workaround is for the DynamicPathVisualizer to create both Earth/Fixed and ICRF Polylines at the time of construction, this way even though it will be empty when the transition starts, it will still have a TWEEN animation set up for it. This fixed is obviously specific to DynamicPathVisualizer, but that's the only place we have this problem right now.

The longer term solution is that we should only have a single TWEEN animation function, and that function should set the morphTime for all primitives in the collection, or primtiives should simply always get the current morphtime from the scene during their update loop. This way if a primitive is added during a morph, it can automatically join in at the correct moprh time and mode.

I'll also add that, technically, there is an additional problem with morphing dynamic paths, because we don't actually morph between the fixed and inertial frames, they snap at the very beginning of any transition in and out of 3D, they just aren't as noticeable. This should be fixable, but is a different (but related) issue.
Fix specs.
Fix race condition in ClockViewmode.synchonize.

Setting values in the view model would cause other values in the clock to change.  Since we want to synchonize the viewModel with all clock settings, we need to copy the current clock settings to temporary variables, and then set from there.
Merge pull request #604 from AnalyticalGraphicsInc/workaround602

Workaround issue #602
Merge pull request #598 from AnalyticalGraphicsInc/czmlClock

Support for CZML defined clocks.
Improve polyline vertex shader performance by removing the inverse cosine and sine function calls.
Add comments with links.
Merge branch 'master' into polylineMaterials