[antlr-interest] updates to visitor/listener naming stuff

[Terence Parr]

Changes:

* names changed. visit() -> visitX(). enter/exit() -> enter/exitX()
* capitalizing automatically now. rule s -> SContext not sContext
* no enter/exit method in generic rule context object if rule has alt labels, nor in interfaces.
* dup labels allowed in same rule
* label X or x illegal if rule x exists

Pushed to parrt/antlr4/master at github.

Ter

Example:

s : e ;

e : e '*' e             -> Mult
  | e '+' e             -> Add
  | INT                 -> primary
  | ID                  -> primary
  | '(' e ')'           -> Parens
  ;

public interface AVisitor<T> {
	T visitMult(AParser.MultContext ctx);
	T visitParens(AParser.ParensContext ctx);
	T visitS(AParser.SContext ctx);
	T visitPrimary(AParser.PrimaryContext ctx);
	T visitAdd(AParser.AddContext ctx);
}

public interface AListener extends ParseTreeListener<Token> {
	void enterMult(AParser.MultContext ctx);
	void exitMult(AParser.MultContext ctx);
	void enterParens(AParser.ParensContext ctx);
	void exitParens(AParser.ParensContext ctx);
	void enterS(AParser.SContext ctx);
	void exitS(AParser.SContext ctx);
	void enterPrimary(AParser.PrimaryContext ctx);
	void exitPrimary(AParser.PrimaryContext ctx);
	void enterAdd(AParser.AddContext ctx);
	void exitAdd(AParser.AddContext ctx);
}