Implement withErrors($validator) for views
Use original key value when updating models.

This is necessary in case the primary key was changed.

Fixes #2414.
Fix failing tests.
Add additional unit test for #2414.
Fix expectations for mock objects.
Merge pull request #2695 from franzliedke/patch-16

Use original key value when updating models.
Merge branch '4.0'
Merge pull request #2692 from jcoetzee/views_withErrors

Implement withErrors($validator) for views
Fix spacing.
Merge pull request #2687 from karptonite/builder_tags

Implements cache tags for query builder from issue #2630
Small tweaks to doc-blocks.
Change __call target.
Resolve from container again in meantime while figuring out issues.
Model cache typo fix
Merge pull request #2707 from semalead/hotfix/model-cache-typo

Model cache typo fix
Register artisan in container for stave off bug reports while I fix issues.
Added getSections() method.

I found that is impossible to get template sections from a View object
so I made it possible. This is good expecially when AJAX comes into
play.
Added renderSections() method.

I found that is impossible to get template sections from a View object
so I made it possible. This is good expecially when AJAX comes into
play.

Since the property 'section' is updated once the View has been rendered,
the correct usage is that:
```php
$view = View::make('pages');
$sections = $view->renderSections();
```
Removed old property.
Removed old code.