Updated to deal with multiple datasets, both sampling methods now work correctly, but the gap list based one turns out to be slower. Might be a data structure issue though, needs optimization.
Updated to deal with multiple datasets, both sampling methods now work correctly,
but the gap list based one turns out to be slower. Might be a data structure issue
though, needs optimization.

uhjish/bx-python,uhjish/bx-python,uhjish/bx-python