Roadmap updates for 0.4
Fix: vertical position differences reversed
Changelog updates for 0.4
Readme updates for 0.4
API documentation updates for 0.4
Pixels comparisons round off <0.5px differences
Readme documents pixel rounding behavior
INTEGRATE: Documentation and polish for 0.4 release

* dev:
  Readme documents pixel rounding behavior
  Pixels comparisons round off <0.5px differences
  API documentation updates for 0.4
  Readme updates for 0.4
  Changelog updates for 0.4
  Fix: vertical position differences reversed
  Roadmap updates for 0.4
0.4.0