New clearer launcher icons

Launcher icons are blurry. I uploaded clearer versions of the icons for mdpi, hdpi and xhdpi (I can also upload ldpi and xxhdpi).

Margin (whitespace) for the new icons is not exactly the same (in the new icons, the document is centered, instead of the whole icon). I can try to provide the icons centered the other way if it is necessary (although I don't know if the result will be blurry or not).