v0.3.0

Release version 0.3.0

### Added
- Guess goal car method.
- Possible inits method.
- Number of cusps.

### Changed
- Return 10 possible goals (5m together) as default.

### Fixed
- Heading overflow/underflow.
- Negative discriminant.
- Parallel parking slot entry find.
- Guess goal method for angled perpendicular parking slots. `guess_gc`
  method now decides if the parking will be forward or backward.
- Perpendicular parking. Not dependent on `fer_perpendicular` anymore.
- Guess goal car for perpendicular parking.

### Removed
- Unit tests removed in `f97dfa1`. Convert it and update tests in the
  future.