[Genome] nib utilities?

[Galt Barber]

We have improved the twoBitToFa help message:

 -seqList=file - file containing list of the desired sequence names
          in the format seqSpec[:start-end], e.g. chr1 or chr1:0-189
          where coordinates are half-open zero-based, i.e. [start,end)


-Galt