Add support for specs [#13]
In rails 4 we should use #render method

Method #render will also execute #tag method. Addition, the name
attribute will be correctly filled.

ActionView::Helpers::Tags::TextField#initialize accept more arguments
compared to ActionView::Helpers::InstanceTag#initialize. Thats why we
can pass input_options as last argument.

In the same way they do in rails:
https://github.com/rails/rails/blob/fb24f419051aec00790a8e6fb5785eeb6f503f4a/actionpack/lib/action_view/helpers/form_helper.rb#L771
Update Rakefile
Merge branch 'support-for-tests-and-rails4' of https://github.com/X8/filepicker-rails

* 'support-for-tests-and-rails4' of https://github.com/X8/filepicker-rails:
  Update Rakefile
  In rails 4 we should use #render method
  Add support for specs [#13]

Conflicts:
	lib/filepicker/rails/form_builder.rb