Fix for issue #5516

Adds scale factor to the HMD absolute positioning

Completed curve docs

Properly detect webGL in example code in the CanvasRenderer documentation

Add position tracking to VRControls

WebGLRenderingContext may return a truthy value even though WebGL is disabled or when a graphics card is blacklisted. I took the check from Detector.js to properly detect for this and reformatted the code for readability.

Docs - Completed small todos

It allows use the mouse to rotate the camera instead of the HMD sensors....

's handy for developing without having to have an HDM connected to the computer

Bringing back functionality from GeometryUtils.merge

Split merge into two functions: mergeGeometry which takes THREE.Geometry as its first param and mergeMesh which emulates the old behavior of the THREE.GeomertryUtils.merge() function which allowed a THREE.Mesh object to be passed.

Disabling scissor test after rendering each frame to leave OpenGL state ...

OrbitControls: Added access to angle values from the outside

Fixed a bug that Detector.webgl becomes null in iOS 7.