examples: add main function
add rudimentary master/controller/client
Remove microcycle unit

Introducing it complicates things and has no advantage with good rational arithmetic support.
language/units: use only a string to identify units
language/units: fix printing
language/units: better support for ops on different dimensions
devices/dds_core: remove stale kernel_attr
py2llvm/fractions: add lt, le, gt, ge comparisons
language/core: add time_to_cycles and cycles_to_time
language/units: add mod
transforms: track units, now() returns seconds, implement time_to_cycles and cycles_to_time
transforms/inline: support attributes on user variables/calls
test/full_stack/pulses: compare results on host and device
add autobuild hook
artiq/devices: add pdq2.py
examples/transport.py: add pdq2 api suggestion
examples/transport.py: refine syntax