capture_RPiHQ.cpp: not so wordy and more
capture_RPiHQ.cpp: not so wordy and more

Remove unneeded Log() entries.
Remove unneeded comments.
Check for failed capture.
Fix bug where RPiHQcalcMean() was called before first picture.
Fixed the "kill" command.
Removed commented-out block that will never be used.
Simplified building of raspistill command line.
Minor tweaks.
thomasjacquin/allsky,thomasjacquin/allsky,thomasjacquin/allsky