add gitignore file, ignore dist/ and docs/
Fix "constant" type interpolator - cheers Terrance
Merge branch 'gitignore' of https://github.com/stepheneb/scenejs into stepheneb-gitignore
new ant tasks: package-lib, packge-examples

If you are modifying the source code and testing it with 
a new example or your own project the following ant tasks 
which complete in just a couple of seconds may be helpful.

ant package-lib

Create the "dist" directory and populate the lib directory with scenejs.js, scenejs.min.js, and the plugins and utils directories.

ant packge-examples

Create the "dist" directory and populate the lib directory and the examples directory.
create index.html when packaging examples

forgot this when refactoring ant tasks
ant package-examples, package-lib don't clean dist/

When hacking on SceneJS or an example it is helpful to
keep the generated documentation while regenerating
scenejs.js, scenejs.min.js and the examples.

The ant tasks: all, package, package-docs, docs clean
the dist directory.

The ant tasks package-examples, package-utils and package-lib
do not clean the dist directory.
horizontal list style for multiple-canvases example
multiple-canvases example

 Multiple Canvases SceneJS scene which renders the venerable OpenGL teapot into four canvases.

 Stephen Bannasch
 sbannasch@concord.org

 Adapted fron the hello-teapot example by:
 Lindsay S. Kay,
 lindsay.kay@xeolabs.com

This example renders separate scenegraphs containing a 
teapot object from different perspectives into four separate canvases.

Dragging in the pitch and yaw axes in any one canvas will 
affect the orientation of the teapot object in the other three canvases. 

Each of the rotatable Newell Teapots are illuminated by 
three light sources from the same direction.
canvas1's yaw should change canvas3's roll
add Z-buffer depth to console info on scene creation

example:

  SceneJS V0.7.9.0 initialised
  SceneJS.Scene binding to canvas 'theCanvas'
  SceneJS.Scene using webgl context with Z-buffer depth of: 24 bits
  SceneJS.Scene logging to element with ID 'theLoggingDiv' - logging to browser console also
  Scene defined: s0
  ...
add ZBufferDepth readable attribute to scene node

example:

  SceneJS.withNode("theScene").get("ZBufferDepth")
  => 24
reset canvas size for webgl when specified with css

When the size of a canvas element is set with css styles
instead of specifying the size in the element itself the
canvas displays using the css styles but reports a default
height and width (300 x 150). 

When creating a webgl context the canvas attributes height
and width are used so if the canvas size is specified with 
a css style the resulting webgl viewport will be incorrect.
new SceneJS.Disk geometry primitive

Example:

Definition of solid disk that extends 6 units radially 
from the Y-axis, is 2 units high in the Y-axis and is 
made up of 48 longitudinal slices:

var c = new SceneJS.Disk({
  radius: 6,      // Optional radius (1 is default)
  height: 2,      // Optional height (1 is default)
  rings: 48       // Optional number of longitudinal slices (30 is default)
})
primitive-objects example: sphere, box, and disk

solid and wireframe renderings
add optional inner_radius param to SceneJS.disk

Example json:

  {
      type: "disk",
      radius: 1.0,
      inner_radius: 0.5,
      rings: 12,
  }
show ring-type disc in primitive-objects example

Example json:

  {
      type: "disk",
      radius: 1.0,
      inner_radius: 0.5,
      rings: 12,
  }
update documentation for ring usage of SceneJS.disk
SceneJS.disk supports optional semiMajorAxis attribute

The optional semiMajorAxis attribute is used to create
elliptical disks.

The default value for the semiMajorAxis attribute is
1 which results in a circular shape. 

The semiMajorAxis attribute is normalized to a unit 
sized radius.

To create an elliptical disk with a real semi-major-axis
of 9 units use the following node attributes:

{
  node: "disk",
  radius: 6,
  semiMajorAxis: 1.5
}
SceneJS.disk attribute inner_radius => innerRadius

to follow convention in rest of codebase.
new: SceneJS.disk sweep attribute

The sweep attribute is normalized to 1 and specifies
an optional rotational extrusion (1 is default).