Adds page#layoutpage to allowed params.
Redirect url display position fix.
Renames `resource_relations` class method into `alchemy_resource_relations`

`resource_relations` is a too common name, that could cause problems.
Fix modules lookup for modules with '/'-prefixed controller names.
Replace dynamic_form gem with simple_form and converts first forms.
Adds a remote form overlay observer.
Converts pages#new and pages#configure_external forms to simple_form.
Adds a `alchemy_form_for` helper that uses a custom builder with custom input wrapper.

Use `alchemy_form_for` like you would with simple_form or rails form helpers.
Refactors `render_errors_or_redirect`.

It now renders the 'edit' or 'new' template instead of injecting errors via javascript.
We also get rid of the render_remote_errors js view.
Initialize overlay tabs after dialog.load not in html partial.
Fixes page forms.
New forms styling.
Updates TODO and converts translations.
Converts all forms into simple form based alchemy forms.
Fixes language tree switching.