Add "Suspend for X minutes" option to gtk-redshift
HACKING: Add further notes on testing python scripts.
Makefile.am: Fix missing files when generating tarball.

With

  $ ./configure --disable-gui
  $ make dist

currently a tarball would be produced, that lacks the .desktop file.
That happens, because an empty variable is appended to EXTRA_DIST.

The attached patch ensures release tarballs with complete, consistent
content and at the same time makes sure that with --disable-gui no .svg
files are installed.
Rename gtk-redshift -> redshift-gtk.

This is primarily for improved discovery. Some users report that they didn't know about redshift-gtk, but had it been available on tab completion they would have noticed. Also, I think it is in general good practice that closely related programs have the same prefix.
Add color calibration support via colord