remove container class and add resetAllcheckbox function

### 1. remove container class

The bbGrid display error when I add bootstrap-responsive.css link.

* css: 
```
...
<link rel="stylesheet" href="stylesheets/bbGrid.css" />
<link rel="stylesheet" href="http://twitter.github.com/bootstrap/assets/css/bootstrap-responsive.css" />
```

* html:
```
<div class="row">
  <div class="span4">left</div>
  <div id="bbGrid-clear" class="span8"></div>
</div>
```

### 2. add resetAllcheckbox() function for thead view

* test example1:
```
new bbGrid.View({
    container: $('#bbGrid-clear'),
    collection: new Backbone.Collection([
        {id: 1, name: 'wenzhixin', company: 'scutech', email: 'wenzhixin2010@gmail.com'},
        {id: 2, name: 'wenzhixin', company: 'scutech', email: 'wenzhixin2010@gmail.com'}
    ]),
    selectedRows: [1, 2],
    multiselect: true,
    colModel: [
        { title: 'ID', name: 'id' },
        { title: 'Full Name', name: 'name'},
        { title: 'Company', name: 'company'},
        { title: 'Email', name: 'email' }
    ]
});
```

* test example2:
```
new bbGrid.View({
    container: $('#bbGrid-clear'),
    collection: new Backbone.Collection([
        {id: 1, name: 'wenzhixin', company: 'scutech', email: 'wenzhixin2010@gmail.com'},
        {id: 2, name: 'wenzhixin', company: 'scutech', email: 'wenzhixin2010@gmail.com'},
        {id: 3, name: 'wenzhixin', company: 'scutech', email: 'wenzhixin2010@gmail.com'},
        {id: 4, name: 'wenzhixin', company: 'scutech', email: 'wenzhixin2010@gmail.com'},
        {id: 5, name: 'wenzhixin', company: 'scutech', email: 'wenzhixin2010@gmail.com'},
        {id: 6, name: 'wenzhixin', company: 'scutech', email: 'wenzhixin2010@gmail.com'}
    ]),
    selectedRows: [1, 2],
    multiselect: true,
    rows: 4,
    colModel: [
        { title: 'ID', name: 'id' },
        { title: 'Full Name', name: 'name'},
        { title: 'Company', name: 'company'},
        { title: 'Email', name: 'email' }
    ]
});
```