Problems so far:
* leaks zombie processes
* does not work when terminating feh with a signal (since the convert process
  is no longer in feh's process group)

This reverts commit 8b79bc33.

This fixes a segfault in --reload when the image becomes unloadable while feh
is running.

Note that this does not affect --reload with more than one file: If the
current image is removed, feh will simply jump to the next image. feh will
only quit if the file still exists, but can no longer be loaded.

67e41d60 moved the ZOOM_MODE from options.h
defines to a feh.h enum, but did not set the values correctly.

By default, feh draws white text with a black drop-shadow, which is well
readable in most, but not all cases.  The --draw-tinted option draws a
semi-transparent black box around all texts.  This improves readability, but
does not look as nice, so it won't become default behaviour.

It was suggested to use #7f7f7f7f for the background, but I decided that
for small images surrounded by a black border.

In the image_remove function, slideshow_change_image needs to be called before
removing the image from the filelist.  Because of this, the "x of y" displayed
by --draw-filename is wrong (y is 1 too high).

This commit introduces a new 'render' argument to slideshow_chingae_image.
The image_remove function calls it with render=0, edits the filelist and then
runs by winwidget_render_image itself.

Patch by Yu-Jie Lin.

Signed-off-by: Daniel Friesel <derf@finalrewind.org>

Use config.mk for configuration, both GNU make and FreeBSD make are supported.