added powerlaw model
inherit from astropy.parameters (this is risky)
fixed powerlaw model - scale & characteristic are 100% degenerate
Merge branch 'master' into astropy-dependent
added astropy model inheritor class
setup.py fix if tests/ subdir already exists
successfully added an astropy model fitting code, though right now it
only works for single peaks, and appears to work very poorly
Merge branch 'astropy-dependent'