me-manu/gammaALPs: New features and bug fixes

This release features several new features and important bug fixes:

• The notebooks in the tutorials now come with syntax highlighting (PR #8), and several bugs / typos in the tutorials where fixed (issues #21, #24 )
• In the helical / tangled jet environment (JetHelicalTangled) it is now possible that the photons are emitted at arbitrary positions (PR #10)
• Additional dispersion terms chi can now be provided as 2D scipy.interpolate.RectBivariateSpline objects and the redshift dependence has been added for mixing in the IGMF (PR #13 #18 )
• The behavior of the logging has been improved by adding a custom logger for (PR #14)
• The EBL environment is now handled like any other environment as a proper transfer matrix (PR #15)
• Fixed bugs in the computation of the Gaussian turbulent field (#20)
• Fixed bug in how final transfer matrix was computed (issue #19, PR #22)