Changes in version 1.25:

Default constructors have been added to classes Block and Sblock.
(Reported by Rosen Penev).

A failure in 'make check', happening when testing under a directory with
spaces in the name, has been fixed. (Reported by David Morrison).

In rescue mode, any non-finished subsector that is now found during the
initial read of the mapfile will be joined to its corresponding sector (if
it is also not finished), marking the whole sector with the less processed
state, so as to make sure that sub-sector data will not be discarded from a
successful read during the rescue. (A subsector is a block smaller than
sector size). (Reported by David Burton).

The time needed to write the mapfile is now excluded from the mapfile save
and sync intervals. (It seems that some mapfiles take 7 seconds to write).
(Reported by David Burton).

Ddrescue now extends the output file using 'ftruncate' if it works, because
it is slightly more efficient.

Large numbers in messages (like device sizes) are now printed in groups of 3
digits separated by underscore '_' characters to make them more readable.
