v0.0.3 Exact infinite frequencies

What's new

• This release replaces the big-M approximation with the modified version of the algorithm given by Spiess & Florian themselves, making the implementation match the paper exactly.
• New tests: TestNoWaitReplacesBasket (a boarding link accepted first is fully replaced by a cheaper no-wait chain) and TestZeroCostChainLoading (regression for loading order at exact zero-cost ties (board -> ride -> alight -> walk)

For the more information see the reference: a21654c