Fixes#661.
BREAKING CHANGE: The binding for ionInfiniteScroll has changed, as well
as how you finish it.
If you had this code before:
```html
<ion-content on-infinite-scroll="doSomething"></ion-content>
```
```js
function MyCtrl($scope) {
$scope.doSomething = function(scrollDoneCallback) {
doSomething();
scrollDoneCallback();
};
}
```js
Now, your code should look like this:
```html
<ion-content on-infinite-scroll="doSomething()"></ion-content>
```
``js
function MyCtrl($scope) {
$scope.doSomething = function() {
doSomething();
$scope.$broadcast('scroll.infiniteScrollComplete');
};
}
```
Adds new '$ionicBind' service, which takes an object containing
binding definitions (similar to angular directive isolate scope
definition). Allows binding of any directive attribute & expressions
from a scope, letting us do normal attribute -> scope binding
without having to create isolate scopes.
Closes#555. Closes#669
BREAKING CHANGE: All directives are now prefixed with `ion-`.
For any directive you use, add the ionic prefix.
For example, change this HTML:
```html
<tabs>
<tab title="home" href="/tab/home">
<content>Hello!</content>
</tab>
</tabs>
```
To this HTML:
```
<ion-tabs>
<ion-tab title="home" href="/tab/home">
<ion-content>Hello!</ion-content>
</ion-tab>
</ion-tabs>
```
