Install reStream downloading the latest release

[f3fora]

People should download last release of reStream and not clone this repo.
I updated the README.md accordingly. See #50
Moreover, I change the structure of that file to avoid repetitions.

[rien]

This is indeed an improvement of the README, thanks!

There are a few minor things I'd like to see changed though.

[rien]

Thank you again!

[f3fora]

I think we made a mistake. We cannot use https://github.com/rien/reStream/releases/download/latest/..., but we have to use the version explicitly.

[rien]

Apparently we need to use https://github.com/rien/reStream/releases/latest/download/... (switch latest and download).

wget https://github.com/rien/reStream/releases/latest/download/reStream.sh works

[f3fora]

Confirm.
At this point, I think it's easier to put a -i flag to install the binary directly, Something, like this.

release-"1.1"

...

	-i | --install)
            ssh $remarkable 'wget https://github.com/rien/reStream/releases/download/$release/restream.arm.static -O /home/root/restream && chmod +x /home/root/restream'
	    shift
	    ;;

In this way we avoid incompatible versions between host and remarkable.
If you want we can add also the other ways to get restream, but this increase the dependencies (wget on host or toltec on remarkable), and if we do not find restream binary on rm, echo "run reStream -i"

[rien]

Yes, this is part of what I want to implement with #50, but I would let the script ask to install or update.