Small installation glitches in 1.2.0

[lgbaldoni]

An empty meson.build file is installed with the themes and im.srain.Srain.Red.png is actually 128x123 instead of 128x128 as per freedesktop specs.

[lgbaldoni]

I also add that the appstream dependency is not checked and on older systems it produces this. But this might be distro-specific, I don't know enough about the matter.

[SilverRainZ]

I also add that the appstream dependency is not checked and on older systems it produces this. But this might be distro-specific, I don't know enough about the matter.

I never meet this on Arch or Debian, and also doesn't know why appstream is needed here. so let it keep unchanged for now.