parser: onleave.opt.
parser: onleave.opt.

	* src/parser/ugrammar.y (onleave.opt): New.
	Use it.
	(ELSE_LESS): Remove, CMDBLOCK suffices.
	(else_stmt): Rename as...
	(else.opt): this.

aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi