Continuum method names need clarity

[wtbarnes]

Per the discussion in Issue #134, the method names in the Continuum module need to be cleaned up a bit. Currently, nearly all of them are prepended with calculate (e.g. calculate_free_bound_emission) though this is a bit annoying when searching for a particular method name. To help users identify method names easier, the calculate should be moved to the end of the name. This also helps autocomplete (e.g. in the Jupyter notebook) be more useful. Note that all of the names and calls to these methods in the Continuum module will need to be changed in addition to any other places where a Continuum class is instantiated, e.g. Spectrum, radLoss

[kdere]

sounds good to me