Fix abnormal display for static stars.

When Black Hole is selected as Live Wallpapers, many mosaic points are shown on the screen instead of the stars.
1). Change the size of staticstar.png and staticstar2.png to power of 2 to avoid display distortion;
2). Increase the scale factor to draw big stars.

Change-Id: I4ca34b72dda285d4d4d2cda7d99c2e2a5e095144
Signed-off-by: Xiaofei Wan <xiaofei.wan@intel.com>