- 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.

- Adds amplitude prefact
- Adds F1
- Reorganise code to aid in future development

Previously, each individual SFT was written separately. This adds
functionality to concatenate all files used `lalapps_splitSFTs`.

Two new Writer classes to generate artifacts with either Frequency
Modulation alone, or Frequency and Amplitude modulation

Previously, the spin-modulation was neglected. This adds it back in and
doubles it to ensure the window covers all the frequencies

- Adds function to use XLALCWSignalCoveringBand
- Fixes issues in injection_helper_function, both are checked to agree

If detectors is not specified, det=None, then in the outfile simply use
'NA' to indicate this.