Fixed bug related to E-MILES library import

Minor change, but essential for correct import of E-MILES SSP library.

Minor bug fixes and inclusion of E-MILES models

• fixed bug #2 and #3 emission lines are now masked correctly also in vacuum and max_ebv behaves as expected
• added possibility to select between vaccum and air to fit in
• reference update in Readme
• added E-MILES models

Minor bug fixes

Minor bug fixes

• default Master model library fixed
• wrong comment removed

New models, update for MaNGA DR17, minor bug fixes

• Added squared grid models of M11-MILES.
• Added MaStar models v.1.1.
• Adapted firefly_manga.py to run DR17 MaNGA data.
• Now uses datacube specific LSF instead of generic MaNGA resolution vector.
• Some minor bug fixes.

Major revision of interface and bug fixes

• Firefly is now called by the script firefly.py (or firefly_sdss.py, firefly_manga.py). All parameters are set through this one wrapper.
• Cap on the maximum number of fit objects to be created per iteration removed, as in some cases it generated a bias in templates files used.
• MaStar models added and some versions of M11 model and BC03 model removed as not working.
• Wavelength dependent instrumental resolution added.
• Improved functionality of emission line masking and masking of individual pixels
• Output reset to model fit in observational data wavelength range

Update to python3

Updates to run Firefly with python3

Read stacked spectra with emission lines masked.

We have included the tested function: stack_no_lines function to read stacked spectra without emission lines. This function has been created for eBOSS spectra with emission lines removed by DAP.
We have also solved minor problem with declaration of globlal variables within python/firefly_fitter.py and updated the link to Comparat+18 paper in the README.md.

Update to mass labels and possibility to use interpolated SSPs

Firefly second release, with two main updates:
i) The labels for the masses have been updated so now the Stellar Mass only refers to the living stars and remnants, but not the gas. There is now a label total_mass for the mass including both the stellar and gas component.
ii) The code has been updated to read new SSPs obtained interpolating in metallicity from the previous ones.