Extended python tests
- Python scripts cleanup
- Added python API tests to cmake
- SPS tests fixes to actually work with hive/steem implementation of SPS:
last_idis NOT implemented in hive/steem implementation of SPS in comparison to our original code,
descendingorder is broken and not working as expected in comparison to our original code,
- Warning: some tests give different daily pay values than expected in orginal implementation tests (requires further investigation).
- SPS tests fixes to work with 30 day voting delay