add option --select-only= (default "l", meaning consider only landscape)
remove -w, not explicit enough; revert multiline "Usage..."

breaks highlighting in emacs
better handle dest_dir
replace ':' by 'x' in generated file names to please vfat
add wallprogress, update README.md
update .gitignore
wallprogress: \n between file name and serial
wallprogress: new options -a and -b