gvfs-copy: Make the progress output usable

Rather than spamming the screen with output, rate-limit the updates and
make them display over each other.

https://bugzilla.gnome.org/show_bug.cgi?id=637543
gvfs-copy: Improve the interactive overwrite

Mimic the output of cp by displaying the full URI and put a space
between the output and the user's input.
Accept either lower or upper-case 'y'.

https://bugzilla.gnome.org/show_bug.cgi?id=637543
gvfs-copy: Show progress for interactive copy

If requested, show progress for an interactive copy.

https://bugzilla.gnome.org/show_bug.cgi?id=637543
gvfs-move: Improve progress output

Rather than spamming the screen with output, rate-limit the updates and
make them display over each other.  Also calculate the speed of
transfer.

https://bugzilla.gnome.org/show_bug.cgi?id=637543
gvfs-move: Improve the interactive overwrite

Mimic the output of mv by displaying the full URI and put a space
between the output and the user's input.  Accept either lower or
upper-case 'y'.

https://bugzilla.gnome.org/show_bug.cgi?id=637543
gvfs-move: Show progress for interactive move

If requested, show progress for an interactive move.

https://bugzilla.gnome.org/show_bug.cgi?id=637543