GitLab

This patch adds two new source files that will deal with code
related to progress callbacks and display. I have decided to
keep this separate, as there will be many smaller routines
involved, which otherwise would bloat fel.c unnecessarily.

For starters, let's also move the gettime() function there.
Signed-off-by: Bernhard Nortmann <bernhard.nortmann@web.de>
Reviewed-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>