wrap of elastic peak for lmfit, argument name in elastic_peak is changed
use consistent name in compton_peak function
write set_default function to wrap parameters for class
add doc for physics_model
add lmfit in yaml
clean up
MNT : removed XR_data

 - a ndarray subclass that did not quite pan out
ENH : dict sub-class which has verbose exception

added verbosedict

 - overrides __getitem__ to provide a more verbose KeyError
 - for small numbers of keys (<25) lists them all in the error message
 - for large numbers, tells you how many there are
TST : added tests for verbose dict
TST/BUG : fix re-raise issue
add test for gauss model, and change output from physics functions as single output
add test for elastic model
add test for compton model
update setup.py file
add __init__ file
update on parameter_data
update compton test
use decimal 2
dict issue for python 3
clean up