Retina display support

i guess it turned out to be harder than expected. The Oxygen style can scale only partially and while there are vector icons (and a high resolution Oxygen icon set), you simply cant make one icon which.looks good in all sizes. Note that retina in the way apple did it it, as far as i know at least, isn't resolution independent either - it is mostly just a doubling of the resolution of everything. Having a scaling of 125% for example is much harder, let alone arbitrary %s.