Config parser should verify that parameters are physically realistic

[Rodot-]

Problem description

tardis will currently run when given negative abundances without complaining. Other physically unrealistic parameters like negative densities are also run without complaint resulting in odd behavior of TARDIS (freezing up for example). We should implement some sort of checks in the config parsers (or when we run tardis) to make sure that the config represents a physically realistic system

[aribalam]

@Rodot- Would like to take this up. Could you point me in the right direction?

[DhruvSondhi]

@andrewfullard this issue can be closed !!