Make repository public

[HannaLindgren]

Depends:

• Add correct references to/license for the original Go lexer #2 - Add correct references to/license for the original Go lexer
• Add correct references to/license for unicode/ICU #3 - Add correct references to/license for unicode/ICU
• Add badges to README (prepared in commented section)
• Go doc comments on all public structs and fields?