Changes in version 1.7:

This version skips very fast over damaged areas.

This version maintains the logfile minimized at all times, improving
efficiency.

The error count now shows the number of error areas found, irrespective
of their sizes.

When splitting, this version jumps to the next non-split area after two
consecutive errors have been encountered in the current one.

Target "check" has been added to Makefile.

The new option "--retrim" has been added.
