Merge branch 'master' into rpi. Upgrade to Cubism 4 R3

diff --cc example/demo.patch
index 10395d7,9c5f42c..af215d5
--- 1/example/demo.patch
--- 2/example/demo.patch
+++ b/example/demo.patch
@@@ -1,10 -1,7 +1,10 @@@
  diff -pruN --exclude build ./demo_clean/CMakeLists.txt ./demo_dev/CMakeLists.txt
  --- ./demo_clean/CMakeLists.txt       2021-02-17 01:23:17.000000000 +0000
- +++ ./demo_dev/CMakeLists.txt 2021-04-28 12:32:48.468744883 +0100
+ +++ ./demo_dev/CMakeLists.txt 2021-06-12 17:14:36.877121318 +0100
 -@@ -3,7 +3,7 @@ cmake_minimum_required(VERSION 3.16)
 +@@ -1,9 +1,9 @@
 +-cmake_minimum_required(VERSION 3.16)
 ++cmake_minimum_required(VERSION 3.13)
 + 
   # Set app name.
   set(APP_NAME Demo)
   # Set directory paths.