Added name parser grammar (kudos to Sylvester Keil)

the grammar is based on names.y from the bibtex-ruby project:
https://github.com/inukshuk/bibtex-ruby/blob/2.3.4/lib/bibtex/names.y

The original grammar is licensed under GPL v3. It has been
converted to ANTLR and is released here under the Apache License 2.0
by permission of the original author Sylvester Keil.