adding a -d option (used by the openqa worker later)

this option avoids writing a file, but sends all output to STDERR. the worker
then will have all output of isotovideo in one file by redirecting stout and stderr
Merge pull request #139 from os-autoinst/no_special_log

adding a -d option (used by the openqa worker later)
trying some new algorithm for the template match

The numbers the matchTemplate function gives us were not reliable for
large needles, so I tried something else and I'm now calculating the MSE
of the area and the scene part found matching.

The MSE I map to a comparable percentage number, following
http://en.wikipedia.org/wiki/Peak_signal-to-noise_ratio example