tower-4 initial pass: excise the Scheduled context
tower-4 rewrite chugging along
worked some codegen in
reasonable codegen story
freertos implementation coming along, type check broken at the moment
fixes - we can now build the freertos foobartest

the generated ivory code works for channels. no dataports yet
reasonable codegen story for dataport in tower
freertos implements refactored dataport codegen
and now graphviz works
update versions to 0.4.0.0