Implements a simple buildspec construction for morphs.

A spec can be generated from a morph with

```js
morph.buildSpec();
```

The result of this is a JSON-like object. For a simple rectangle this
produces:

```json
{
  _ClipMode: "visible",
  _Extent: "<eval>lively.pt(100.0,100.0)",
  _Position: "<eval>lively.pt(38.0,514.0)",
  _Rotation: 0,
  _Scale: 1,
  className: "lively.morphic.Box",
  droppingEnabled: true,
  halosEnabled: true,
  name: "Rectangle1",
  showsHalos: false,
  sourceModule: "lively.morphic.Core",
  submorphs: []
}
```

To create a morph from a spec use

```js
morph = lively.morphic.Morph.fromSpec(spec);
```
adding a window switcher
cleanup
config option and auto-load for window switcher
fixing window switcher for 0/1 windows
oops, don't want t disable all keydown events...
Merge pull request #114 from LivelyKernel/window-navigation

Window navigation