Game Update

The game now uses the new language element case and stores sprites and tilemaps in :sprite and :tilemap so that the j-ocoto tile and sprite editors are able to access the data from the source code.

The tilesets of level 2 to 4 have been changed. Level 4 got a new deadly plant and a break, so it is more complicated.

Two tapes for the ZX Spectrum have been added which allow to play the game at a ZX Spectrum 48 K or better. One contains my super chip 8 emulator, the other contains the re-compiled game, which runs about 2-3 times faster than the emulated one.