handle brightness+contrast from msoffice (bnc#875713)

This is the same like 1139d618b8bc6ab823a96184bd0f0257980aad24, for docx.

(cherry picked from commit 893fe88469dec5b727d96f8ea1b4edb9e88288a7)

Conflicts:
	oox/source/drawingml/fillproperties.cxx

Change-Id: I1ef4e18444e8c60e9ae8f67249bcef1053f0d62d
Reviewed-on: https://gerrit.libreoffice.org/9217
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>