Namespace helper functions (to avoid conflics w other modules)

There are two functions, is_page_allowed() and is_role_allowed() that could possibly conflict with similarly named functions in other modules (or themes). It is a best practice to namespace all functions in a module with the name of the module to avoid any potential conflicts.

The function is_page_allowed() could be renamed crazyegg_is_page_allowed() or even _crazyegg_is_page_allowed(). Some maintainers like to name their internal functions with an underscore, to signal to other maintainers that these functions should not be called directly from outside this module.