species v0.2.2

• Support for Exo-REM model spectra in add_model, FitModel, and ReadModel.
• Storing the spectral resolution of each spectrum from an object.
• FitModel uses the spectral resolution to smooth the model spectra with a Gaussian.
• Fast convolution with smooth_spectrum when the wavelength sampling ha a uniform spectral resolution.
• Added the absolute_to_apparent function to convert absolute to apparent magnitudes.
• Added the update_spectra function for updating the spectra of an object with a best-fit scaling and/or error inflation.
• Optional scaling parameter in FitModel that can be fitted for each spectrum.
• Added teff_labels parameter in plot_color_magnitude.
• Added get_magnitude and get_color_magnitude in ReadPlanck.
• Compatibility of plot_color_magnitude with color-magnitudes from ReadPlanck.
• Factor 4 bug fix in the flux from ReadPlanck.
• Legend **kwargs in plot_spectrum.
• Several minor bug fixes and improvements.
• Updated documentation.