MiniMaven: only complain about parent mismatches in debug mode

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: handle OS family activation for 'unix' and 'mac', too

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: do not complain when systemPath dependencies are 'overridden'

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>