Keep aspect ratio of channel logos

[kecksk0enig]

Hi! This has been an major issue for me, because I have set up many channellogos which are not squared. so I did this fix by myself.

Adistionally wit his change we will no longer reserve the memory for channellogos, if they where disabled.

I tried to match against your codestyle/ format but was unable to get it comletely done.

If you prefere code formatted in your style please provide usable code formatter.

Aditionally I fixed the German translation as a native speaker.

Thx for providing this nice app!

Ps: feel free to contact me if there is anything I can do to get this pulled.