Add a lint indicator that replaces Brackets lint indicator

Removes default Brackets lint status indicator.
Replaces the `errorIndicator` with this `lintIndicator`.

See #61 for more detail on the reasons for this. 
yeah disable is the cleanest way: 

```javascript
CommandManager.get(Commands.VIEW_TOGGLE_INSPECTION).setChecked(false);   
CommandManager.get(Commands.VIEW_TOGGLE_INSPECTION).enable(false);  
```