[Dillo-dev] Doxyfile

I have removed all boilerplate from Doxyfile, now it is much shorter and there are less empty/default vairables. I was looking for some way to change layout to something simplier (no CSS-based tabs for example), but looks it is easier to just disable CSS. Cleaned up Doxyfile attached. I have enabled DOT_MULTI_TARGETS to make building faster and left TODO for Dillo logo.