High score table and other fixes

The game has a high score table including entering a player's name, if the game is running on Spectrum 128K (and compatibles) or Didaktik Gama.

The monkey "dance" music at the end of the game has a better volume envelope when played on the AY sound chip, making it sound closer to the original arcade game.

A graphical error in the introduction (after certain GAME OVERs) is fixed.

An error that did not affect Spectrum because it was only trying to write to ROM, but caused errors on SAM Coupé, is fixed.