add fine cuts to bldice

[jeenriquez]

Is your feature request related to a problem? Please describe.
Not a problem, but a limitation.
Currently bldice cuts to the nearest coarse channel end. This makes for us, but maybe not for the rest of the world.

Describe the solution you'd like
Having an option to cut at any frequency maybe useful for some.

[mattlebofsky]

Maybe this is obvious, but I suggest that it cuts to the nearest coarse channel (inclusive) by default, which is its current behavior, and any finer cuts are overridden by a command line option. We don't want current pipelines to break due to new, unexpected behavior.

[jeenriquez]

yep, this is the way to go. coarse channel granularity should be default.