New functions of Power&Q window

A new Energy in dense regions only option has been added in the View- Power&Q co-processing. It allows space-selective integration of energy. When it is checked, the software takes into account only the regions composed of the media previously declared as having non-zero density (in the Parameters-Media window of QW-Editor). Thus if one wants to calculate the energy stored in a part of a resonator, and take only this part into consideration when calculating the Q-factors, one should fill this part with a medium of non-zero density and use Energy in dense regions only option.

Moreover, improvements have been made to saving  Power & Q results. Saved files now bear a meaningful *.pq3 extension (instead of earlier *.txt) and include more detailed file header.