version 0.99 rc1: hardcore mode, enemy updates

# fixed the enemy aiming bullets procedure
* enemies fire their bullets centered too! (even the large bosses)
* you may NOT have any multiples together with beams, just lasers
+ added new enemy guns: quad- and 6x-fire!!
* sprite table length increased to 768 bytes (stored DIV3)
+ ships 3/4 select hardcore mode: score and damage are doubled
+ first icon not only increases armor, but also activates shield for
   some time (shield halves damage and absorbs bullets in normal mode)
+ ship selection screen also shows ship specs (hardcore/tailbeam/etc)
* shield looks different for each ship
* hiscore/savegame procedure optimized (several bytes smaller)
+ B<>W mode setting will be stored
* enemy sprite pointers stored as words (thus increasing sprite table
   length from 768B to 65kB, and increasing sprite calculation speed)
+ new bosses
* hardcore mode does _more_ than doubled damage (bulletsdamage +1)