refactor(refresher): allow refresher content customization

Breaking Change:

## Refresher:

- `<ion-refresher>` now takes a child `<ion-refresher-content>`
component.
- Custom refresh content components can now be replaced for Ionic's
default refresher content.
- Properties `pullingIcon`, `pullingText` and `refreshingText` have
been moved to the `<ion-refresher-content>` component.
- `spinner` property has been renamed to `refreshingSpinner` and now
goes on the `<ion-refresher-content>` component.
- `refreshingIcon` property is no longer an input, but instead
`refreshingSpinner` should be used.

Was:

```
<ion-refresher (refresh)="doRefresh($event)"
pullingIcon="arrow-dropdown">
</ion-refresher>
```

Now:

```
<ion-refresher (refresh)="doRefresh($event)">
  <ion-refresher-content
pullingIcon="arrow-dropdown"></ion-refresher-content>
</ion-refresher>
```

ionic/util/dom.ts

@@ -45,6 +45,7 @@ export let CSS: {
   transform?: string,
   transition?: string,
   transitionDuration?: string,
+  transitionDelay?: string,
   transitionTimingFn?: string,
   transitionStart?: string,
   transitionEnd?: string,
@@ -80,6 +81,9 @@ export let CSS: {
   // transition timing function
   CSS.transitionTimingFn = (isWebkit ? '-webkit-' : '') + 'transition-timing-function';
 
+  // transition delay
+  CSS.transitionDelay = (isWebkit ? '-webkit-' : '') + 'transition-delay';
+
   // To be sure transitionend works everywhere, include *both* the webkit and non-webkit events
   CSS.transitionEnd = (isWebkit ? 'webkitTransitionEnd ' : '') + 'transitionend';
 })();
@@ -156,7 +160,7 @@ export function windowLoad(callback?: Function) {
   return promise;
 }
 
-export function pointerCoord(ev): {x: number, y: number} {
+export function pointerCoord(ev: any): {x: number, y: number} {
   // get coordinates for either a mouse click
   // or a touch depending on the given event
   let c = { x: 0, y: 0 };
@@ -243,7 +247,6 @@ export function closest(ele: HTMLElement, selector: string, checkSelf?: boolean)
 /**
  * Get the element offsetWidth and offsetHeight. Values are cached
  * to reduce DOM reads. Cache is cleared on a window resize.
- * @param {TODO} ele  TODO
  */
 export function getDimensions(ele: HTMLElement, id: string): {
   width: number, height: number, left: number, top: number
@@ -268,6 +271,10 @@ export function getDimensions(ele: HTMLElement, id: string): {
   return dimensions;
 }
 
+export function clearDimensions(id: string) {
+  delete dimensionCache[id];
+}
+
 export function windowDimensions(): {width: number, height: number} {
   if (!dimensionCache.win) {
     // make sure we got good values before caching