#222 OwlExt::TBmpMenu does not use system colors properly

[Vidar Hasfjord]

When using OwlExt::TBmpMenu, the top-level menu bar items are drawn with the TColor::SysMenu (COLOR_MENU) background color. On XP and later this should be COLOR_MENUBAR, like the rest of the bar. Also, the background of the pop-up menu and transparent bitmaps should use TColor::SysMenu (COLOR_MENU), not TColor::Sys3dFace (COLOR_3DFACE).