wmaker: Consistent configuration options.

wmaker: Consistent configuration options.

The default configuration options are given in two places in the source
code:
  - src/default.c
  - WindowMaker/Defaults/WindowMaker.in

The defaults are initially set in the former, but are then overwritten by
the latter.

Ideally, the default options in these two locations should coincide.
However, there are currently several issues.
- Many of the options are missing from WindowMaker/Defaults/WindowMaker.in
- Many of the options have conflicting defaults between the two locations.
- A number of options given in WindowMaker/Defaults/WindowMaker.in no longer
  exist.

In this patch, we bring the defaults in the two locations in line with one
another.  We have given preference to the defaults in W/D/WindowMaker, as
these are the one users have been used to.

Some of the paths in IconPath and PixmapPath have been removed.  In
particular, the various system pixmap paths (/usr/include/X11/pixmaps,
/usr/share/pixmaps, and /usr/local/share/pixmaps) have been removed in
favor of PIXMAPDIR, which is specified by the user at build.  Also,
/usr/share/icons has been removed from IconPath.  The root of this
directory will contain very few icons, as the icons themselves are located
in subdirectories corresponding to XDG icon themes.

We add a comment to src/defaults.c to remind future developers who
add or remove options to change the default values in both locations.

We also take the opportunity to remove the unused DEF_INFO_TEXT_FONT
macro.