This adds a new method `setup_initialisation` which can be called to run
the initialisation step. Splitting it out from the main functionality
should make it easier for new users.

- Provide a function in the BaseSearchClass to read in the ephemeris
  files
- Some clean up of docstrings

- Remove arbitrary dpi choices
- Set the xlimits to remove white space before and after

- Converts coordinates to more usual Alpha. Delta F0, F1 ordering
- Adds debug info on the Nstar for each dimension
- Returns maximum Nstar iterating over each set of dimensions (not
  completely, just [0], [0, 1], [0, 1, 2], etc.

This helps with timing to see which functions are being called
repeatedly

- Adds autocorrelation attempt (using PR 223 to emcee)

- Adds return_type option to return (by default) a Bunch class such that
  the attributes can be accessed as `out.F0`, `out.F1` etc
- Improves documentation

- Cleans up convergence messages
- Adds autocorrelation calculation
- Provide acccess to `c` parameter
- Improve overall documentation of run()

- When Alpha and Delta are not given, use a simple sin
- Also fixes error in DeltsFSpin when Alpha and Delta are given
- Removes Alpha and Delta from MFDv4 call since they are not used

Since each SFT is generated in a for loop, the process can be quite
slow. This allows the user with `pathos` multiprocessing installed to
leverage `-N` cores (set by command line arg) to speed the process up
Setting N=1 or if pathos is not installed, reverts to the usual
behaviour.