Add Mega Everdrive style header detection for homebrew using the SSF2 mapper, though without the Mega Everdrive extensions. Properly invalidate translated code on a bank switch when using the SSF2/Sega mapper

#ifndef PPM_H_
#define PPM_H_

void save_ppm(FILE *f, uint32_t *buffer, uint32_t width, uint32_t height, uint32_t pitch);

#endif //PPM_H_