Parameterize target tolerances

[MattHJensen]

Parameterize upper and lower tolerances for each target.

(Discussed on a call between Peter and Matt on 7-13-20)

[Peter-Metz]

@MattHJensen I've started parametrizing constraint tolerances in the new get_constraint_bounds() method. Here's how it works:

• There's a boolean parameter called Aggregate_tol_all that controls whether or not the user wants to specify different tolerances for different constraints, or whether they are happy imposing the same tolerance for all the constraints.
• If Aggregate_tol_all is True (which is the default value), the user can choose the constraint tolerance with Aggregate_tol.
• If Aggregate_tol_all is False, the user can specify a tolerance level for each constraint with the parameters *_tol (for example, A00200_tol).
• Similarly, there is a parameter called Addup_tol which allows the user to specify the tolerance for the adding up constraint. I believe one could turn the adding up constraints off by setting the tolerance to 9e99.

Let me know what you think about this approach conceptually. I still have to do lots of testing.