KeplerGO/lightkurve: Lightkurve v1.0b22

Lightkurve v1.0b22 includes the following changes lightkurve.open() was added to provide a single function to read in any light curve or target pixel file from Kepler or TESS and return the appropriate object [#317]; the from_fits() methods have been deprecated in favor of lightkurve.open() [#336]; the lightkurve.mast module has been removed in favor of the new lightkurve.search module; various small bugfixes, speed-ups, and documentation improvements [#314, #315, #322, #323, #325, #331, #334, #335]