Initialize the muscle table before parsing the command line.

	* src/getargs.c (quotearg.h, muscle_tab.h): Include.
	(getargs): Define file_name.
	* src/main.c (main): Initialize muscle_tab before calling
	getargs.
	* src/muscle_tab.c (muscle_init): No longer define file_name, as
	its value is not available yet.