capture_RPiHQ.cpp: saveImage.sh
capture_RPiHQ.cpp: saveImage.sh

Added many changes to implement saveImage.sh.
Made several variables global so they could be used by multiple functions.
Added some variables to configure the name of the file written to disk:
  * save_dir is the directory the file is written to
  * final_file_name is the "image-DATETIME.jpg" name
  * fileNameOnly is just the file name without extension or directory
  * full_filename is the name of the image file including its directory
Moved bound checking for "quality" variable to main() since main() now uses it.
Added error checks for valid image file name extension and valid image type (RGB26, RAW8, RAW16).
RPiHQcalcMean() takes the open cv::Mat instead of the image file name.
Call saveImage.sh, passing several arguments, rather than saveImageDay.sh and saveImageNight.sh.
thomasjacquin/allsky,thomasjacquin/allsky,thomasjacquin/allsky