make it clear to not use instant contiki

01-install-contiki.org

@@ -28,10 +28,11 @@ Here are some of them:
 2. Install under Docker
 3. On Windows, install a virtual machine and install Ubuntu then install on that
 4. Use Vagrant to help with installing on a virtual machine
-5. Download Instant Contiki
 
 We go with option 4 as it allows us to use an up-to-date Contiki-NG but simplifies some of the install issues.
 
+Please do NOT install InstantContiki as this is an older version of Contiki with slightly different behaviour.
+
 * Check that virtualisation is turned on
 Before you start, check that virtualisation is turned on
 + See https://bce.berkeley.edu/enabling-virtualization-in-your-pc-bios.html