Draft: Some improvement for 1.2.0

1- Add new commands: bgradient, colcalib, colcalibphoto & satucmd to allow scripting with full gui parameters. 2; Add comment/message to output/log for commands: asinh, clahe, crop, fixbanding, fmedian, neg, rgradient, rl, rmgreen, satu, wavelet & recons.

Comment are of the form: CMD: <parameters....> This allow to use the log file by a bash script to build a post process script for siril. Usefull to replay a post processing on a pre processed fit file. Also usefull to build models/templates for specific observations.

Notice that I have put many comments inside the code because initially it is for my own and because I doesn't use gitlab. I want to easily refind my moficiations. Those comments can probably be removed.