IP_Address changes:
- Converts to and from String transparently while handling IPv4 as IPv6
mapped (::ffff:[IP]) address internally.
- Completely remove AddrType enum.
- Setting/Getting of ip array is now only possible through dedicated functions
(ie. set_ipv4, get_ipv4, set_ipv6, get_ipv6)
- Add function to know if the address is a valid IPv4 (for IP implementation and enet)
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.
