[TwigBridge] Added form_twitter_bootstrap_layout.html.twig
feature #10272 [TwigBridge] Added form_twitter_bootstrap_x.y.z_layout.html.twig (lyrixx)

This PR was merged into the 2.6-dev branch.

Discussion
----------

[TwigBridge] Added form_twitter_bootstrap_x.y.z_layout.html.twig

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | not yet

Doc:

``` yaml
# config.yml
twig:
    form:
        resources:
            - form_twitter_bootstrap_2.3.x_layout.html.twig
```

or

```jinja

{% form_theme form 'form_twitter_bootstrap_2.3.x_layout.html.twig' %}

{{ form(form) }}
```

Commits
-------

cfc04a6 [TwigBridge] Added form_twitter_bootstrap_layout.html.twig