vcldemo: exercise more BitmapEx rendering paths.

Change-Id: Iecd02534dfbe0938a8635e3b7c2363b4531ef5ef
vcldemo: BitmapEx rotation, translation and shear.

Change-Id: I5a44597bc39c6bccfcec32403fae8f8d7d4fe94c
vcldemo: implement key-bindings and command-line

Change-Id: I98ea70a78f340a2050ef934de3111ba3191ff479