Hendrics

Fix bug 139

+ Based on [Stingray 1.0](https://github.com/StingraySoftware/stingray/releases/tag/v1.0-beta), bringing a huge bump in performance
+ Energy-filtered periodograms
+ Many fixes to mission-specific files
+ Better info returned by Z searches, including pulse amplitude estimates
+ Add ability to split files at a given MJD
+ New upper limit functionality in Z searches with no candidates

HENDRICS 6.0 depends on Stingray >=0.3.
In this release, all the improvements from the Stingray release plus:

+ Much improved mission support
+ Lots of performance improvements, especially for large input event files.
+ Improved simulation and upper limit determination for Z searches
+ Improved candidate searching in Z searches
+ Documentation fixes
+ Fixes to the `HENfake` simulation script

which introduced:

> - Lomb-Scargle periodograms and cross spectra are now available
> - Power colors
> - Easy filling of small gaps in light curves with random data
> - Generic timeseries (complex data, multi-dimensional data)

- `HENaccelsearch` now has additional options for detrending,
denoising and deorbiting

- An improved Maximum likelihood algorithm as FFTFIT substitute for
TOA calculation

- NASA\'s IXPE added to supported missions

- Better support of Stingray\'s native file formats