Revert changes

Revert previous changes that caused unforeseen errors

`_None_` for non-searchable arguments

_None_ can now be used for non-searchable arguments

Fixed issue with argument parsing in a list

Fixed

• Bug with negative numbers in lists as strs

Changed

• Delimiter of nargs of searchable argument from ~~ to |
• Util name form list_as_dashed_str to list_as_delim_str
• Default delimiter in (now) list_as_delim_str changed to , (avoids errors with negative numbers)

Minor bug fix

v1.5.2

Update changelog

Bug fixes on configuration file argument

Fixed bug where config file would not override unspecified arguments that had a default value.