[development] hook_depend()

Hi. What about implementing hook_depend(). I mean module that depends on some module (e.g. taxonomy) must define function modulename_depend() { return array('taxonomy'); } Then if user has no taxonomy module turned on - he/she will be asked to do so or not. If not - he/she will be told that modulename can't be installed. Also when user disables taxonomy module then he/she will be told that modulename depends on taxonomy module and so modulename will be also turned off.