Ability to import Jremapper/Enigma mappings

[artemking4]

Ability to import mappings of Enigma/Jremapper

Import mapping files from tools like Jremapper/Enigma

[Col-E]

Remapping right now is really only intended for one class at a time. Some refactoring would be required to make it viable to do large-scale renaming.

Definitely on the TODO list.

[Col-E]

Added on the 2.0.0 branch in af8fa08