Move top-level typedefs to typedefs.js

With one exception, those directly in the `ol` namespace can be moved without problem.
Some left-over goog.requires are also removed.

src/ol/feature.js

@@ -1,5 +1,4 @@
 goog.provide('ol.Feature');
-goog.provide('ol.FeatureStyleFunction');
 
 goog.require('goog.asserts');
 goog.require('ol.events');
@@ -284,18 +283,6 @@ ol.Feature.prototype.setGeometryName = function(name) {
 };
 
 
-/**
- * A function that returns an array of {@link ol.style.Style styles} given a
- * resolution. The `this` keyword inside the function references the
- * {@link ol.Feature} to be styled.
- *
- * @typedef {function(this: ol.Feature, number):
- *     (ol.style.Style|Array.<ol.style.Style>)}
- * @api stable
- */
-ol.FeatureStyleFunction;
-
-
 /**
  * Convert the provided object into a feature style function.  Functions passed
  * through unchanged.  Arrays of ol.style.Style or single style objects wrapped