JDFTx Inputs - boundary value checking

[benrich37]

Summary

Major changes:

• feature 1: Revised boundary checking for input tags
  -- Added a validate_value_bounds method to AbstractTag, that by default always returns True, ""
  -- Added an alternate AbstractNumericTag that inherits AbstractTag to implement validate_value_bounds properly
  --- Changed boundary storing to the following fields
  ---- ub and lb
  ----- Can either be None, or some value to indicate an upper or lower bound
  ---- ub_incl and lb_incl
  ----- If True, applies >= instead of > in comparative checks on upper and lower bounds
  -- Switched inheritance of FloatTag and IntTag from AbstractTag to AbstractNumericTag
  -- Implemented validate_value_bounds for TagContainer to dispatch checking for contained subtags
  -- Added a method validate_boundaries to JDFTXInfile to run validate_value_bounds on all contained tags and values
  -- Added validate_value_boundaries argument for initialization methods of JDFTXInfile, which will run validate_boundaries after initializing JDFTXInfile but before returning when True
  --- Note that this is explicitly disabled when initializing a JDFTXInfile from the input summary in a JDFTXOutfileSlice - boundary values may exist internally in JDFTx for non-inclusive bounded tags as the default values, but cannot be passed in the input file. For this reason, errors on boundary checking must be an easily disabled feature for the construction and manipulation of a JDFTXInfile, but out-of-bounds values must never be written when writing a file for passing to JDFTx.

Todos

• feature 1
  -- Implement some way boundary checking can run when adding tags to a pre-existing JDFTXInfile object
  --- boundary checking is currently only run when initializing from a pre-existing collection of input tags
  --- writing this into JDFTXInfile.__setitem__ is too extreme as it would require adding an attribute to JDFTXInfile to allow disabling the check
  --- the better solution would be to implement a more obvious user-friendly method for reading in additional inputs so that the user doesn't need to learn how to properly write out the dictionary representation of complicated tag containers.
  -- Fill out reference tags for other unimplemented boundaries