Update hyperpe

Here's an updated version of hyperpe, it's a little more general and allows multiple sampled parameters to be considered(I should probably add an example doing this). It's a little rough around the edges but I think it's functionally where it needs to be.

Changes are:

• It takes a list of pandas data frames, this could be tupak result objects but that might be overly limiting.
• It downsamples the posteriors to make the likelihood evaluation use array operations. By default, it uses the length of the shortest chain, you can also specify how many samples to use, but it won't use more than the shortest chain.

Things that need to be done:

• Update the docstring
• Remove the old version