Delay opening the destionation file and other fixes.

Delay opening the destionation file and other fixes.

The opening of the destination file is now delayed a little.
The coder is initialized, and if decompressing, the memory
usage of the first Block compared against the memory
usage limit before the destination file is opened. This
means that if --force was used, the old "target" file won't
be deleted so easily when something goes wrong very early.
Thanks to Mark K for the bug report.

The above fix required some changes to progress message
handling. Now there is a separate function for setting and
printing the filename. It is used also in list.c.

list_file() now handles stdin correctly (gives an error).

A useless check for user_abort was removed from file_io.c.