updated script for .deb files with SD, including new sd.xpm #81

Updated script make-deb.sh to produce SD.deb that works on 18.04 & 20.04 LTS.

Some quesions I have that we talked about on TG:

Is it possible to install a hushd deb and then install this SD deb?
- Right not it seems that they might "fight" over installing hushd/hush-cli, but maybe it "just works"
If I install hushd deb, then SD deb, then decide I don't want the SD deb and uninstall it, does it remove hush-cli from the system? That would be pretty weird.

My philosophy in the past was that hushd was responsible for all the "low level" files, such as sapling params, asmap.dat and the hushd/hush-cli/hush-tx binaries. This allows us to keep SilentDragon debs small and simple. The idea is that people need to install the hushd deb, then the SD deb.

It also kept the file size of SD deb under 100MB, which I think was a problem in the past. We can maybe make SD deb "smart" and only install hushd/hush-cli/asmap.dat if they are not there already, in the case that they do "fight" or conflict.

And thanks for the new xpm file! 👍

I know on Arch Linux, if one package had already installed hush-cli, then the 2nd package trying to install hush-cli would fail and its package manager pacman would tell you it's already owned by the other package.

I believe we should keep the CLI tools installed only by the hushd package.

I will update it to only include hushd + silentdragon binaries.

what about embedded hushd @duke ?