Convert model and view `actual` mappings to `tail()` functions.

Remove the `actual` member on the kernel's model and view arrays since
that complicates initialization. Replace with a `tail()` function
directly on the drivers and stages that locates the end of the pipeline.

Replace:
  - kernel.models.actual[...] with kernel.models[...].tail()
  - kernel.views.actual[...] with kernel.views[...].tail()
Convert vwf.js to a RequireJS module.

- Call define() with *logger* and *vwf/configuration* as dependencies.
- Convert public members to members of an *exports* object.
- Convert private members to internals of the module function.
- Remove JSDoc @name overrides since JSDoc can parse the module.
- Remove the vwf.js <script/> element and add "vwf" to the require()
  dependencies in index.html and the tests.
Move other module references to define() dependencies and remove the
require() calls.
Don't create the logger in initialize() since the module load creates
it.
Don't keep a reference to the configuration settings on the kernel
module.

It's directly available as the configuration module.
Change internal references to the kernel to use `kernel` instead of `vwf`.

Removes confusion with the (soon to be removed) window global `vwf` and
reinforces the documentation convention of referring to the kernel API
as `kernel.function` (in contrast to `model.function` and
`view.function`).
Use the module kernel reference in internal functions.

Have the kernel internal functions find the kernel using the `kernel`
internal variable rather than using `this` and requiring the caller to
invoke them as `function.call( kernel, ... )`.
Add configuration control of the pipeline stages.

- Add settings in configuration.js for model and view drivers.
- Support pipeline stages for view drivers in the kernel.
- Enable `vwf/model/stage/log` in development mode only (remove from
  `production` and `testing`).
- Remove assumptions in `vwf/model/glge` about the length of the model
  pipeline.
Rename the kernel global `vwf` to `vwf_deprecated_global`.

For testing (breaks everything).