Update install docs to mention use of prepare-build.sh for package builds.

Soft removal of jessie support (just remove the build docs)

README.md

@@ -20,6 +20,8 @@ many other Linux or Unix-like systems.
 
 ```bash
 $ sudo apt-get install build-essential fakeroot debhelper librtlsdr-dev pkg-config dh-systemd libncurses5-dev libbladerf-dev libhackrf-dev liblimesuite-dev
+$ ./prepare-build.sh buster
+$ cd buster
 $ dpkg-buildpackage -b --no-sign
 ```
 
@@ -27,32 +29,11 @@ $ dpkg-buildpackage -b --no-sign
 
 ```bash
 $ sudo apt-get install build-essential debhelper librtlsdr-dev pkg-config dh-systemd libncurses5-dev libbladerf-dev
+$ ./prepare-build.sh stretch
+$ cd stretch
 $ dpkg-buildpackage -b --no-sign
 ```
 
-## Building under jessie
-
-### Dependencies - bladeRF
-
-You will need a build of libbladeRF. You can build packages from source:
-
-```bash
-$ git clone https://github.com/Nuand/bladeRF.git  
-$ cd bladeRF  
-$ git checkout 2017.12-rc1  
-$ dpkg-buildpackage -b
-```
-
-Or Nuand has some build/install instructions including an Ubuntu PPA
-at https://github.com/Nuand/bladeRF/wiki/Getting-Started:-Linux
-
-Or FlightAware provides armhf packages as part of the piaware repository;
-see https://flightaware.com/adsb/piaware/install
-
-### Dependencies - rtlsdr
-
-This is packaged with jessie. `sudo apt-get install librtlsdr-dev`
-
 ### Actually building it
 
 Nothing special, just build it (`dpkg-buildpackage -b`)