feat($compile): allow disabling scope info

The compiler adds scope information (`ng-scope` CSS class and `$scope` data property) to elements
when the are bound to the scope. This is mostly to aid debugging tools such as Batarang. In
production this should be unnecesary and adds a performance penalty.

In the bench/apps/largetable-bp this change caused an improvement of ~100ms (7%).

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 ~120ms, that is ~10%.
Measuring the "create" phase, 25 loops, mean time ~1200ms -> ~1080ms.