ColorCodes: treat "code" as semantic noise.

We want to allow the string "code" to be used in the triggering query,
but we want it to have no effect on how the query is understood
or processed.

Addresses issue #454.
DatesRole: Making vaguestring regex available
DatesRole: Adding support for "jan 1st" "13 march" to vague
DatesRole: cleaning up clashing variables and making use of vague_datestring_regex not pollute the consumer's match context
WorkdaysBetween: Using new DatesRole functionality to fix https://github.com/duckduckgo/zeroclickinfo-goodies/issues/346
BinaryLogic: Original version by @bpaschen
BinaryLogic:minor cleanup
Removing Xor, superceded by BinaryLogic
BinaryLogic: Harmonising the test format
BinaryLogic: Commenting out failing test until I can figure out why
DatesRole: Refactoring date_regex into a builder
DatesRole: renaming usages of date_regex() to $formatted_date
DatesRole: Renaming things inline with "datestring" for regexes and moving  date_output_string to keep parsers together
DatesRole: Separating parse_string_to_date and formatted_strings to date behaviour
DatesRole: Wrapping and renaming parse_descriptive_string_to_date to parse_descriptive_string_to_date
DatesRole: inverting if in descriptive parsing
DatesRole: Tidyup
DatesRole: Adding tests for new datestring_regex methods and renaming existing regex
DatesRole: Adding tests for the formatted_datestring_regex and switching existing tests to use it versus the date_regex()
DatesRole: Switching invalid string tests from parse_string_to_date to parse_formatted_datestring_to_date