Updating supported device info
Removed the "Pi 3".  There really is only the Pi 3B and Pi 3B (aka Pi 3).
Also strengthened the language about the Pi 2.
@@ -58,20 +58,18 @@ This section of documentation assumes the following:
* Pi3 B+ : SUPPORTED <-- You should get this device if you want to work on Picroft
* Pi3 B : SUPPORTED <-- You should get this device if you want to work on Picroft
-* Pi3 : SUPPORTED <-- But not the primary target for development.
-* Pi2 : functions but very slow <-- Only use this if you must
+* Pi2 : functions but very slow, limited wifi support. Not recommended.
* Pi B/A+/Zero/Zero W/Zero WH : NOT SUPPORTED
##### Required
-* Raspberry Pi 3 (see compatibility chart above)
+* Raspberry Pi 3/3B+ (see compatibility chart above)
* Micro SD card, 8GB or larger _highly_ recommended
* Power adapter with micro USB for your country. [The Raspberry Pi Foundation has some excellent recommendations](https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md).
* An analog Speaker that can be plugged into the 3.5mm audio jack on the RPi 3
* USB Microphone
-
##### Optional
* USB keyboard
