Moving edit_read_line() and simple_read_line() to loaders.c, and

Moving edit_read_line() and simple_read_line() to loaders.c, and
extending them to support reading MS-DOS, Mac and UNIX style files
on all platforms.

Modifying read_config_line() (without changing it's prototype) to
be a trivial wrapper for edit_read_line().  This means that we have
one function to read a line and handle comments, which is common
between the initialization code and the edit interface.