Improve colors in widget && rm unused icons.

Improve colors in widget && rm unused icons.

1. Set window background color to transparent so it will have "round
   corners".
2. Remove ambient background color definitions, now whole widget
   background will be white.
3. Remove unused icons.

Change-Id: Ie6429c3a8a5bb80e5243d1df881377b254c33a2a
Signed-off-by: Ernest Borowski <e.borowski@samsung.com>