actually read brightness/contrast when reading docx (bnc#875713)

It's read for the shape in oox/ , but it didn't make it any further apparently.

Change-Id: I0885a675f72d63b3d262f1ef7e42f5d2e03588b6
handle brightness+contrast from msoffice (bnc#875713)

This is the same like 1139d618b8bc6ab823a96184bd0f0257980aad24, for docx.

Change-Id: I1ef4e18444e8c60e9ae8f67249bcef1053f0d62d