增加ColorPalette的背景
#	new file:   ColorPalette/res/drawable-xhdpi/bg.jpg
#	new file:   ColorPalette/res/drawable-xhdpi/bg1.jpg
#	new file:   ColorPalette/res/drawable-xhdpi/bg2.jpg
#	new file:   ColorPalette/res/drawable-xhdpi/bg3.jpg
#	new file:   ColorPalette/res/drawable-xhdpi/bg4.jpg
#	modified:   ColorPalette/res/layout/activity_main.xml
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