this fixes a problem where some ROMs when given the command line
directive to use the PAL spec is contradicted by the preview emulation.
this seems to be a particular problem with PAL ROMs that never set a
valid VSYNC signal. Nightstalker is a good example of such a ROM
notifications interface instance moved to environment from
cartridgeloader. the cartridgeloader package predates the environment
package and had started to be used inappropriately
simplified how notifications.Notify() is called. in particular the
supercharger fastload starter no longer bundles a function hook. nor is
the cartridge instance sent with the notification
preview can be used to run a ROM for a short period in order to gather
information about the ROM that can only be found through execution. this
is useful for example, for setting the TV dimensions
