did not allow 1.01
Merge branch 'master' of github.com:antlr/grammars-v4
ABNF: add reference to RFC errata

Hex digits are case-insensitive according to the errata. It is apparently a common misunderstanding that the RFC only allows upper-case hex digits.
Merge pull request #112 from nathansgreen/patch-1

ABNF: add reference to RFC errata