Add filename to "Export Raw Project..." names to allow multiple tilesets per project

[pvmm]

Adding a prefix based on the name of the project, for instance a "stars" project exports variables with a "STARS_" prefix:

// --- Defines for Metadata ---
#define STARS_PROJECT_TILE_COUNT      36
#define STARS_PROJECT_SUPERTILE_COUNT 9
#define STARS_SUPERTILE_GRID_WIDTH    2
#define STARS_SUPERTILE_GRID_HEIGHT   2

This allows the user to import multiple projects into the same source code. This is useful for reusing different maps for a game by just replacing tile patterns and colours.