chrishks's sandbox: Page manager permissions

This module adds permissions for the CTools' Page Manager to allow more granular control of which buttons/tabs/pages within pages that users can access. This can be useful in cases where you want content editors to be able to change titles, layout templates or panel content but want to restrict access to more technical features such as contexts.

Currently Page Manager has two permissions: 'administer page manager' and 'use page manager'. Page Manager Permissions extends the permissions available so access to individual pages (and custom pages) can be defined, and access to settings within the variants sections can be defined.

The default permissions from Page Manager are not overwritten, only added to. This means users will most likely need to have 'use page manager' as well as the relevant permission from this module to access a particular section. However, 'Administer page manager' still gives access to everything (so a user with that permission will have access to everything defined in Page Manager Permissions).