using t() function in file header

using the t() function in the head of the module file is critical. at this time, no locale informations are available. so if you do not use english as your default language, every page request ends up in writing the locale cache again. in clustered environments with master-slave db setup, this could become a big problem.

simple patch is, to declare that constants using the init-hook. at this time, locale_initialize() got called and every is fine ... :-)