Theming app: also change other icons to selected logo

[jancborchardt]

The other icons like favicon are not changed yet. We should have some code to automatically convert the logo in to all the different things like favicon and mail header icon.

cc @schiessle @LukasReschke

[MariusBluem]

It is also possible to change the login-logo independent from the logo on the top by creating an theme. Shouldn't this also be possible with theming?

[jancborchardt]

@Mar1u5 no, we intentionally phased out that difference, and we'll keep it that way to make theming as simple as possible first. We still need to fix some stuff there, so this is not the time to complicate it yet. :)

[juliusknorr]

I've played a bit with generating dynamic icons, it is still quite a mess, but I'm working on this. SVG support in Imagemagick is really crappy. 😞

[blizzz]

Looks like bigger changes, due to the RC knocking at the door, let's also move this milestone to 11.