Changes in version 1.6:

Displaying of null characters by the "l" command has been fixed.

The condition deciding when to show the message "Newline appended" has
been corrected.

The "modified" flag is now set when reading a non-empty file into an
empty buffer.

An error that prevented using NUL characters in regular expressions has
been fixed.

Ed now signals an error if it can't create a shell process when
executing a shell command.

Ed now flushes stdout/stderr before reading a new command.

Man page is now generated with "help2man". All command-line options are
now documented in the man page.
