Implements notification images, reboots USB bus if camera isn't found, adds error checking.

Implements notification images.  Allows users to specify via config file if bad images should be removed.  Removed duplicate code.  Added return code checks.

Added some error checking.  Added COPY_TO_WEBSITE and RESIZE_UPLOADS options.  Added lftp commands to upload temporary file name, then move to permanent name, to help avoid issues with slow upload speeds.

Minor updates.

Implement notification images.
Dark frame from "capture" is now called "dark.$EXTENSION" to distinguish from normal image.
Used $IMG_PREFIX.

Does error checking on "convert".
Lets user know if they've set DARK_FRAME_SUBTRACTION on but have no darks.

Saves "keogram" and "startrails" output in temp files rather than putting the 1000+ lines in the log file.
Runs "removeBadImages" based on "$REMOVE_BAD_IMAGES" in config.sh.
Only upload keogram and startrails if they were successfully created.

Mention adding "$ME" to any messages.  "$ME" is the command name, and is useful to have in the log file to know which command produced the output.

Added $DATE and $DIR for readability.

Implemented $ME.
Commented out line since endOfNight.sh prints a similar line.
Removed unnecessary double quotes on lftp line to make it easier to read.

Removed check for DARK_MODE since darkCapture.sh exits the script if DARK_MODE is on.
Moved "identity" check to top; there's no need to do anything else if the image is corrupt.
Perform error checking on "convert".
Allow user to specify thumbnail size and resize size.
Implement $IMG_PREFIX instead of hard-coding "liveview-".
Removed unnecessary double quotes on lftp line to make it easier to read.

Removed check for DARK_MODE since darkCapture.sh exits the script if DARK_MODE is on.
Moved "identity" check to top; there's no need to do anything else if the image is corrupt.
Perform error checking on "convert".
Allow user to specify thumbnail size and resize size.
Implement $IMG_PREFIX instead of hard-coding "liveview-".
Removed unnecessary double quotes on lftp line to make it easier to read.
The final image name is always the same now, so it's no longer "image-processed.jpg" if dark subtract is on, and "image.jpg" if it's off.  That was confusing.

Optionally also checks for too dark and too bright images, based on REMOVE_BAD_IMAGES_THRESHOLD_LOW and REMOVE_BAD_IMAGES_THRESHOLD_HIGH from config.sh.
NOTE: I'm not sure how to do that check if "parallel" is used.
Removes bad thumbnails in addition to bad images, and displays reason they are removed.
Centralized redundant code for easier maintenance.
Outputs a summary line.

Allows timelapses to be created for images no in ~/allsky/images.  For example, for observatory cameras.
Save "ln -s" output to temp file rather than outputting 1000+ lines to log file.  temp file is save so user can look at it, and a summary is output.
Perform error checking.
Decreased useless output from ffmpeg.
lftp puts to a temp name, then renames it to the correct name.  This is because timelapse files are large and if the web server tries to read the file as it's being uploaded, it will get an error.

Implement $ME.
Remove unneeded double quotes in lftp.
Removed "-u $USER,$PASSWORD" since it's not needed.

Mention new settings and new names to existing settings.
Note that many of the settings (now and prior to these changes) don't apply to Pi cameras; I didn't do anything about that.

I'm assuming the will be version 0.8, so added summary of changes.

Keep prior log file to aid in debugging.
Ability to reset the USB bus if the ZWO camera isn't found.
Put settings in a bash array, so they can have spaces in them.
Optionally display "notification" images.
Checks if output is a tty (user invoked it manually) or not (service invoked it) - this is used by capture program to display appropriate log messages.

Includes new variables.

Added new and renamed settings.

Add new settings.  Changed names on others.

Added many of the changes from the ZWO capture.cpp file to keep both files in better sync.

NOTE: I don't have an RPiHQ camera so was unable to test the new version.  It compiles, however.

NOTE: I suggest removing the unused code from capture.cpp (it's commented out).  It makes the file harder to read.

Lots of updates from Eric Claeys and Linda xxx
Workaround for ZWO auto exposure bug (included in #ifdef USE_HISTOGRAM blocks - on my default).
Improved exposure algorithm that decreases sensor temperature about 10 C.
Better exposure transition between day and night when gain is different.
Many new settings and many old ones changed names.  The recently submitted allsky-portal knows about these changes.
Lots of error checking.
Optionally displays "notification" images, like "Taking darks".
On user error, displays a message and waits for the user to fix it, rather than exiting, restarting, exiting, etc.
Gracefully exits when service sends SIGTERM signal.
Lots of comments and additional debugging code added (based on actual problems people had).
Handles dark frames better.