Fix transparency bugs, remove topLeft, layers positioning (use css)
layers: absolute rather than fixed positioning; demos: 0x0 test canvas
index.html page lists sample, test models and doc

Create index.html at root of repo for looking at samples
and doc to make it easier for someone who clones repo to
investigate.

Also makes creation of useful gh-pages branch easier.
add additional contributors section to readme.md
Add ability to attach a spotlight to an agent

Calling Model.setSpotlight(agent) will add a "spotlight"
to an agent, similar to the NetLogo "follow" function.
This allows a user to easily follow a single agent.

The spotlight is removed when Model.removeSpotlight()
is called, or when the agent dies.

There is also a shortcut for Model.setSpotlight(breed),
which will pick a random member of a breed.
Merge branch 'cc-spotlight' into cc
adaptation of Bob Tinkers Global Climate model

Adaptation of a simpler version of Bob Tinkers (Concord Consortium)
Global Climate NetLogo model.
add CC Samples to index.html page
use d3 v2.10 built for Lab instead of D3 v3
adaptation of Bob Tinkers Solar Panel 2.0 model

AgentScript adaptation of Bob Tinkers (Concord Consortium) Solar Panel 2.0
NetLogo model.
use @patches.minX, minY, maxX, and maxY
Climate model: Fix several bugs in model

- Sunlight should start from top
- delete all agents at start so we don't increase
CO2 every time we reset
- Fix add/subtract clouds
Climate model: Allow following of sunlight or CO2

Add buttons for setting a spotlight on a random
sunlight or CO2 agent.
Climate model: hand-pick sunrays for spotlighting

Pick a sun ray that has just come into the model when
following, to better show the lifecycle of an energy
packet. If we can't find a new one, just pick any
random sun ray.

Also fix headingUp calculation (agent.heading can
be > 2pi).
Climate model: Add CO2 graph