Do not use for anything, this is just snapshot of a test in progress. I solved quite a few issues, but many things are still clumsy and broken.

Lots of code got cleaner with seconds, seems we used them before all around.

Also changed examples that didn't need deltas to simple Date.now() plus some more examples cleaning, trying to get rid of obsolescence warnings.

Got tired of redoing deltas all the time. Not sure about API or implementation details, but so far seems to be useful.

In future, we could for example have clocks that are slower / faster than realtime, or fixed step based.

Do not merge, this is very experimental, not sure about correctness, also tons of unsolved things.

* Camera is now a base object. PerspectiveCamera should be used instead. Figured out a way to show a warning when misused.
* OrthoCamera is now OrthographicCamera.
* Removed `target` from Camera.

Misc
* Renamed Trident to Axes.

* Camera.useTarget is now false by default. Updated some of the examples. I tried to remove target altogether (and use lookAt every frame), but I found that WebGLRenderer's ShadowMaps uses a camera with target. Will try again at some point.
* Object3D.lookAt now checks if it's a Camera and does the inverted view.
* Quaternion glitch reported at #595
* Added .name to Material
* WebGLRenderer .clear() to .clear( color, depth, stencil ). All of them true by default.

Fixed mergeVertices(). Moved from CubeGeometry to Geometry. Now checkDupVertices(true) removes duplicated vertices

Rename SubdivisonGeometry.js to SubdivisionGeometry.js. Fix geometries which use duplicate vertices. SubdivisionGeometry tested with Cube/Sphere/Cylinder/TextGeometry

Problem was that objects could be added to WebGLRenderer's internal render list only once (because of `webglInit` flag).

Now there are two separate internal states (`webglInit` and `webglActive`) so that object can be initialized just once (expensive operation) but added / removed from the scene many times (cheap operation).

This buggy pattern ("something = parameter || nonzero value") exists at more places though elsewhere setting to zero doesn't make that much sense (e.g. in geometries).

Not sure if we should change it everywhere to proper pattern ("something = ( parameter !== undefined ) ? parameter : value").

Maybe it would be good for establishing habit. I remember fixing this buggy pattern long ago but it just keeps popping up.

Simplified `Trident`.
Added `setX`, `setY`, `setZ` methods to `Vector3`. They're handy for oneliners (see `CylinderGeometry`).

`renderers/Projector.js` > `core/Projector.js`

`extras/geometries/Curve.js` > `extras/core/Curve.js`
`extras/geometries/CurvePath.js` > `extras/core/CurvePath.js`
`extras/geometries/Path.j`s > `extras/core/Path.js`
`extras/geometries/Shape.js` > `extras/core/Shape.js`
`extras/geometries/TextPath.js` > `extras/core/TextPath.js`