Unit consistency check

In nfwMCMC.py M_200 is in terms of 1e14 Msun,
in MCMAC.py M_200 seems to be in terms of Msun,
and both codes use profiles.nfwparam() to some degree. 

If we were to only keep one version of profiles.nfwparam(),
we should decide on a convention and modify the discrepant code according to this version.
