tmf: Fix event table item default colors and foreground positions

tmf: Fix event table item default colors and foreground positions

The default system colors should be used whenever the default color
setting from the color setting manager is used. This no longer requires
special handling since if the color from the default color setting is
null. The current theme's system colors are not necessarily equal to
COLOR_LIST_BACKGROUND and COLOR_LIST_FOREGROUND.

The background needs to be drawn in the custom EraseItem listener if the
item background is different from the table's background (set to the
default system color as it is never changed), not when it is different
from COLOR_LIST_BACKGROUND (which may not be the default system color in
the current theme).

The text bounds and image bounds adjustments in the custom PaintItem
listener need to be set differently for Windows and Linux.

Change-Id: I06e6ed48e866ce7831ea3ad630d120a8cf228973
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-on: https://git.eclipse.org/r/44124
Reviewed-by: Hudson CI
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>