Restore the WKT parser, example & tests

This is a first attempt to restore the WKT parser.
It is probably preferred to rewrite the parser to the `ol.format` namespace as well,
but I would first like to have some confirmation on this before doing so.
For consistency, can you write this as follows:
```js
  this.splitCollection_ = goog.isDef(options.splitCollection) ?
      options.splitCollection : false;
```

I can't provide a better justification than consistency.