This implements support for exposure times via fti_oversample in the jktebop alternate backend.
TODO:
[ ] decide whether this should be in a bugfix (in which case needs API docs stating when it became available) or the next 2.5 release (in which case would need to be rebased)
[ ] use filters instead of twigs (probably requires refactor in compute.py so that all backends that support exposure time can pull in those parameters)
This implements support for exposure times via fti_oversample in the jktebop alternate backend.
TODO:
compute.pyso that all backends that support exposure time can pull in those parameters)Closes #700