Include paths are processed from left to right, so we use Prepend to
ensure that paths to bundled thirdparty files will have precedence over
system paths (e.g. `/usr/include` should have lowest priority).
The pattern and replacement matching behaviour has been changed purely
due to the nature of switching to a standards-compliant library.
One mistake in the previous behaviour was that named groups didn't have
a number. This has been corrected.
As names are actually just an alias of numbered groups,
RegExMatch::get_name_dict() is now get_names() and is a dict
referring to the group number it represents.
Duplicate names are enabled and the with the first matching instance
used.
Due the lack of a suitable equivalent in PCRE2, RegExMatch::expand() was
removed.
Re-wrote nrex as a module using godot-specific parts and new
features:
* Added string substitutions.
* Named groups are now supported.
* Removed use of mutable variables in RegEx. RegExMatch is returned
instead.
