
1.0 - fixed bug in the algorithm allocating bits from the middle when
      the delta was only 1 bit
0.9 - fixed bug centermost algorithm :
      at the very first round the bit following the center for the even 
      number of bits was not picked
      - from Muggle L <muggle19355--at--gmail.com>
0.8 - added checking of semantical correctness of input prefix
      (if there are non-zero bits after prefix length boundary,
      prefix is considered bad and ipv6gen exits with error.)
0.7 - added stepping between generated prefixes as input parameter
0.6 - fixed RFC 3513 non-compliancy bug (ipv6gen appended :: after
      prefixes longer than 112 bits)
0.5 - fixed zero padding bug - ipv6gen incorrectly generated prefixes
      not aligned to byte boundary. e.g. /64 prefixes were incorrectly
      generated from /49 prefixes)
0.4 - fixed bug when generating bits for middle allocation and 
      delta with even number of bits 
0.3 - check for format of IPv6 prefixes
0.2 - implemented allocation from the middle
0.1 - only allocation from the left/right is implemented
