slightly tuned favicon

Hi there ;)

i have decided to slightly tune current CakePHP favicon on the 
occasion of upcoming 3.0 release. The new .ico file contains
16px and 32px icons with transparent background which looks
good even when using dark browser theme. For both versions i've
decided to center cake picture inside background badge as no text
is present. It looks better IMHO. For 16px version - instead of
simply resizing, i drew a circle/shadow shape from scratch, placing
cake on top and throwing few pixels here and there to correct
aliasing in some places. I can provide source files if needed :)

Comparison (new / old):
![Preview](http://kminek.pl/screen.png)

regards