Update Scene.html

it's -> its

Update ArrowHelper.html

Fixed 'WebGLRenderer.clear' method's description

WebGLRenderer's documentation incorrectly stated that if no parameters were passed to it, the 'clear' method will not clear any buffers. The default behaviour is in fact the opposite: if an argument is undefined, the corresponding buffer will be cleared. The document now correctly describes the default behaviour.
Source code of the method: https://github.com/mrdoob/three.js/blob/master/src/renderers/WebGLRenderer.js#L368

PnlTri.js Rev. 2.0: now handles vertices and edges on other edges (co-linearity)

fix ColladaLoader- result.scene must be a Scene to be renderable

Conflicts:
	examples/js/renderers/SoftwareRenderer.js

Demos with ground planes have consistent up

Give the demos with ground planes of some sort a consistent "up"
direction for the camera, instead of having rotation be able to change
this. Simple change: Trackball to OrbitControls.

platformer example

Changed it so .makeRotationFromEuler accepts Euler