A cairo animated clock

[jenshannoschwalm]

1. The first commit is just maintenance.
2. Second commit implements a cairo-animated clock as a replacement for the svg thing. I personally prefer this but for sure it's just my preference and i don't have a strong opinion on this.

@ralfbrown the splash work is your baby
@TurboGit either just take the first commit or if there is strong consensus on the second commit take that too. :-)

[TurboGit]

Ok for commit 1. The second one will have to wait for 5.2, I do prefer the cairo based implementation here, just that it is too late for 5.0.

[TurboGit]

I have cherry picked the first commit.

[jenshannoschwalm]

Ok, removed the first commit as merged and leaving this with a changed title for 5.2