v0.3.1

What's Changed

• faster index computations, and candidate faster greedy and optimal implementations
• allow single term pre-processing in order to support arbitrary einsums
• change 'flops' to everywhere be scalar operations not specialised to real float dtypes (results in halving cost in various places)
• more preparation to fully decouple from opt_einsum
• more robust path caching for many parallel processes
• add utils.perverse_equation and utils.tree_equation
• add CI testing
• Adding fallback for kahypar version number check by @emprice in #25

Full Changelog: v0.3.0...v0.3.1