Added just the mandatory [testing] sections into all

config files. The files were not modified otherwise.
The added section is, however, empty (all is commented out).

M    config/config-middleVOI-lowSNR.ini
M    config/config-smallVOI-highSNR-correctSize.ini
M    config/config-smallVOI-highSNR.ini
M    config/config-smallVOI-lowSNR.ini
M    config/config-singleCell-correctSize.ini
M    config/config-middleVOI-highSNR.ini