Stage 1

+ void Disk::format(string &)
+ int Disk::howmuchempty( )
+ void Disk::alloc(DATtype &, unsigned int, unsigned int)
+ void Disk::allocextend(DATtype &, unsigned int, unsigned int)
+ void Disk::dealloc(DATtype &)
* moved data init to new func void Disk::resetDat()
+ intmap* Disk::DiskMapping( DATtype& dat)