Created Timer class
Added constructors in Timer
Implemented method start
Implemented private method getTimeOfsettMillis
Implemented method isTimerDone
set startTime to 0 in constructor
implemented method setTimerLength
added Timer-reference in Spaceship
implemented use of timer in method fireWeapon
implemented timer in spasechip and removed debuggingcode
changed getTimeOfsettMillis in Timer to return long to fix problem caused by typecasting