Add a dependency on the Cacheable Cookie Handling module

Here is a patch.

-function cacheable_csrf_menu() {
-  $items['cacheable-csrf'] = array(
-    'type' => MENU_CALLBACK,
-    'page callback' => 'cacheable_csrf_set_token',
-    'access arguments' => array('access content'),
-  );

With this patch we aren't checking "access content" anymore. We could do it manually in the new hook (before setting the cookie) but I didn't see any obvious reason this permission check was needed in the first place? (Seems like it should be theoretically possible to deliberately use this module with users who can't access content, if you want to...)

-  drupal_add_http_header('Cache-control', 'no-cache, no-store');
-
-  // Support Akamai Edge-control headers.
-  drupal_add_http_header('Edge-control', 'bypass-cache');

This is removed in the patch (and is not something that the Cacheable Cookie Handling module does in its Ajax callback). However since in practice the Ajax callback is called via POST, it shouldn't matter?

If it's needed after all for some reason, we can do a separate patch for Cacheable Cookie Handling that adds these headers there.