start of sweep device code
fix SweepEntry doc
improve plan_sweep docs
document device attributes used
WSA4000: add sweep device constants
plan sweep first simple test
start of work on plan_sweep
first working plan_sweep
fix for first plan_sweep test
more simple plan_sweep tests
plan_sweep double test
use SweepStep namedtuple
more tests
plan_sweep: test and fix for fshift
use math.ceil instead of -ve integer division
plan_sweep: start of decimation handling
plan_sweep: decimation tests and fixes
plan_sweep: fstop is redundant
plan_sweep: truncate to left-hand sweep area for now
add sweep_iterations command