feat($compile/ngBind): allow disabling binding info

The compiler and ngBind directives add binding information (`ng-binding`
CSS class and `$binding` data property) to elements when they are bound to
the scope. This is only to aid testing and debugging for tools such as
Protractor and Batarang. In production this is unnecessary and add a
performance penalty.

This can be now disabled by calling `$compileProvider.debugInfoEnabled(false)`
in a module `config` block:
```
someModule.config(['$compileProvider', function($compileProvider) {
  $compileProvider.debugInfoEnabled(false);
}]);
```

In the bench/apps/largetable-bp benchmark this change, with debug info disabled,
improved by ~140ms, that is 10%.
Measuring the "create" phase, 25 loops, mean time ~1340ms -> ~1200ms.

We were storing the whole `interpolationFn` in the `$binding` data on
elements but this function was bringing a lot of closure variables with it
and so was consuming unwanted amounts of memory.

Now we are only storing the parsed interpolation expressions from the
binding (i.e. the values of `interpolationFn.expressions`).

BREAKING CHANGE:
The value of `$binding` data property on an element is always an array now
and the expressions do not include the curly braces `{{ ... }}`.