v1.4.0

• Optimisations and code quality improvements in sequences coprime pairs search callables
• Naming related deprecations of all callables with the term "elements" (replacement with callables named with term "coefficients")
• Some improvements in core lib. error handling
• New lib. for rational points in the plane, including height functions/properties in the setting of projective space $\mathbb{P}^2(\mathbb{Q})$
• Update unit tests
• Add and update Sphinx docs