Improve update-* scripts: Abort early if `git pull -r` fails.

May fail if there are unstaged changes.
Use multi line prompt including current time and git status.
Make multi line prompt more fancy.

Show basename of current directory (and host, if not local) in second line, use only dark gray color for first line.
Show current project (if any) in line 2.
Show full path in lighter grey in line 1.