Fix destination of cancel link for new CIPs.
Remove hacky CIP route helper.

Explicitly check for CIP in form and tab helpers.
Extract instantiation into new_edition method.

This will allow overriding in subclasses.
Simplify CIP admin controller.

* Remove find_corporate_information_page before_filter, and change instance vars
to refer to @edition (as defined by superclass find_edition) rather than
@corporate_information_page.
* Move find_organisation to prepend_before_filter, to ensure it runs first.
* Remove new and create methods as functionality is completely provided by
superclass.
* Remove build_corporate_information_page, and instead override new_edition
which is called from superclass build_edition.
* Remove other methods which are no longer needed (cip_owning_organisation,
params_filters, saved_confirmation_notice).
* Rewrite destroy along lines of superclass method - still need to define it
here though, as both message and redirect destination are different.
Remove unnecessary check and parentheses.
DRY up edition_classes/edition_type_options.