todo
neaten
remove unused make quivers

this was left over from early development when I wanted to check that
the code was doing something. No longer logical to have this
functionality here.
parallel processing decorator

decorate functions that are going to be fed to parallel_process with
parallel_stub. This decorator does the progress bar update and appends
to the queue.

sensible specification of arguments in parallel_stubs (no dictionary
unpacking within functions now), but can only use kwargs.
todo
use wavelets package