Wrap up TR2X/GM support

Resolves #59. #### Checklist - [x] I have read the [coding conventions](https://github.com/LostArtefacts/TR-Rando/blob/master/CONTRIBUTING.md#coding-conventions) - [x] I have read the [testing guidelines](https://github.com/LostArtefacts/TR-Rando/blob/master/CONTRIBUTING.md#testing-guidelines) - [x] I have added a changelog entry about what my pull request accomplishes, or it is an internal change #### Description Final push for GM and TR2X. I'm sure there will be issues found in testing, but will deal with those as they come. I'll update the readme and using files fully on release so it's accurate with the current version. - Added translations (thanks to @LillyJericho and team) - this includes supporting partial translations so e.g. Norwegian only has GM strings defined, so we use English defaults for anything missing if it's used in base TR2. - Added a return path to a couple of GM levels that may need it for keys or secrets, and altered routes accordingly - Fixed a couple of texturing issues, and an incorrect enemy alias level mapping