version 0.99 pre3: updates to bullet weapon, enemies

version 0.99 pre3: updates to bullet weapon, enemies

* beamweapon can be selected when you got laser (like vice versa)
* selecting laser removes tailbeam or up-double
# tail beam/up-double correctly centered
# disappearing bullets (when enemies fired multiple bullets) fixed
+ bullets and lasers both upgradable upto level 9
# fixed end story (_vputs didn't recognize 0-end when "'" in string)
# stars couldn't be altered anymore since recent levelformat changes
* maximum different enemies increased from 28 to 63
* pickup sprite altered, small changes to some enemies
+ new moves implemented: 75% speed and lure-while-moving