Added some comments to sun_map_parse_read().

Added some comments to sun_map_parse_read().

* amd/amd.h: Added an extern from info_file.c called
file_read_line().  Previously this function was static but is now
used in sun2amd.c.

* amd/info_file.c: Changed the static function read_line() to a
public function called file_read_line().  This function is now
used in sun2amd.c

* amd/sun2amd.8: Filled in the contents of this man page.  This is
a conversion utility that converts Sun maps to Amd maps.

* amd/sun2amd.c: Implemented a working version of this utility.