Change option -i to -o.

Now notes are organized with flag -o instead of -i. -o is easier to
remember.

Signed-off-by: Niko Rosvall <niko@ideabyte.net>
Prevent unnecessary file access.

If .memo file is empty don't try to read notes from it. This commit also
uses custom function to check if file exists instead of using access().

Signed-off-by: Niko Rosvall <niko@ideabyte.net>
Handle empty lines and empty note file.

No unnecessary work is done if the memo file is empty. An empty line is
no longer appended to the memo file.

Signed-off-by: Niko Rosvall <niko@ideabyte.net>
Improve error reporting.

If there are no notes, it's reported for the user rather than failing
silently.

Signed-off-by: Niko Rosvall <niko@ideabyte.net>
Version 1.3

Signed-off-by: Niko Rosvall <niko@ideabyte.net>
Make help (-h) shorter.

Memo manpage has full documentation, there's no need to have the same
information in the basic help.

Signed-off-by: Niko Rosvall <niko@ideabyte.net>
Add version 1.3 news

Signed-off-by: Niko Rosvall <niko@ideabyte.net>