existing modern devices and the legacy wrappers to work in this
environment. This in general greatly simplifies writing a modern
device. [Aaron Giles]
General notes:
* some more cleanup probably needs to happen behind this change,
but I needed to get it in before the next device modernization
or import from MESS :)
* new template function device_creator which automatically defines
the static function that creates the device; use this instead of
creating a static_alloc_device_config function
* added device_stop() method which is called at around the time
the previous device_t's destructor was called; if you auto_free
anything, do it here because the machine is gone when the
destructor is called
* changed the static_set_* calls to pass a device_t & instead of
a device_config *
* for many devices, the static config structure member names over-
lapped the device's names for devcb_* functions; in these cases
the members in the interface were renamed to have a _cb suffix
* changed the driver_enumerator to only cache 100 machine_configs
because caching them all took a ton of memory; fortunately this
implementation detail is completely hidden behind the
driver_enumerator interface
* got rid of the macros for creating derived classes; doing it
manually is now clean enough that it isn't worth hiding the
details in a macro
