Made group-names also contain digits.
Merge pull request #67 from bkiers/patch-1

Made group-names also allow digits.
Lua.g4:operator precedence and associativity

I've updated Lua.g4 to include correct operators precedence and associativity.

The format of the associativity tag is the one compliant with Antlr 4.2.2-alpha001
Merge pull request #69 from xanathar/patch-1

Lua.g4:operator precedence and associativity
Merge branch 'master' of https://github.com/antlr/grammars-v4