Doing type checking with isinstance instead of class names

`|css_class` will be kept for backwards compatibility, however is not a
good practice to type check this way, as subclasses don't get recognized
as these types, because they don't have `__name__` attribute set the same
way as the parent class.

Patch for issue #176
Adding `form_show_labels` helper attribute
Added `FormHelper` custom form/formset template attribute
Adding an aditional formset template, thanks to @runekaagaard

This template is heavily inspired by @runekaagard work in
django-crispy-forms-fancy-formsets. A great application for rendering
formsets and handling them in the client using javascript.

By default this template will render a formset within a table with
inline fields. This can be used thanks to the new and shiny helper
custom helper template attribute.

    author = Author.objects.get(pk=id_author)
    BookInlineFormSet = inlineformset_factory(Author, Book, extra=2)
    formset = BookInlineFormSet(request.POST, instance=author)
    helper = FormHelper()
    helper.template = 'bootstrap/table_inline_formset.html'

Then within template:

    {% crispy formset helper %}
Improving docs, adding formsets section

Simplifying index and redoing migration section a little bit
Updating FAQ
Creating a `FormHelper` section in docs and reodering parts
Adding `render_crispy_form` to docs
Adding `update_attributes` method to docs
Adding `field_template` helper attribute
Refactoring styling
Adding a warning to `field_template` attribute docs
Updated copyright information
Improving from_iterable to fix KeepContext issue #180

This fixes issue #180 and adds a test for avoiding regressions
Fixing test case for uni_form
Added Alert class and template to allow for Twitter Bootstrap Alert pane.