Use generator/pyproject.toml to define version

gen/c: Don't add signal queue when len is zero

c-gen: Add version info to output

c-gen: Simplify signal queue

ci: Fix generator path

Bump to 0.5.2

ci: generator: Update req file on build

Merge pull request #27 from jonasblixt/0.5-dev

0.5 Mega commit

core: bugfix: enter and leave sibling states

core: Use negative return values for errors

core: enter_parent_states cleanup

core: Call ufsm_least_common_ancestor from main transition function

core: Add some comments to the code

bugfix/test: Remove unused flags