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

diff --combined example/demo.patch
index 10395d7,9c5f42c..af215d5
--- 1/example/demo.patch
--- 2/example/demo.patch
+++ b/example/demo.patch
@@@ -1,15 -1,12 +1,15 @@@
  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.
  -set(SDK_ROOT_PATH ${CMAKE_CURRENT_SOURCE_DIR}/../../../..)
- +set(SDK_ROOT_PATH ${CMAKE_CURRENT_SOURCE_DIR}/../CubismSdkForNative-4-r.2)
+ +set(SDK_ROOT_PATH ${CMAKE_CURRENT_SOURCE_DIR}/../CubismSdkForNative-4-r.3)
   set(CORE_PATH ${SDK_ROOT_PATH}/Core)
   set(FRAMEWORK_PATH ${SDK_ROOT_PATH}/Framework)
   set(THIRD_PARTY_PATH ${SDK_ROOT_PATH}/Samples/OpenGL/thirdParty)
@@@ -22,15 -19,6 +22,15 @@@
   set(CMAKE_CXX_STANDARD_REQUIRED ON)
   set(CMAKE_CXX_EXTENSIONS OFF)
   
 +@@ -42,7 +42,7 @@ add_library(Live2DCubismCore STATIC IMPO
 + # Find library path.
 + set_target_properties(Live2DCubismCore
 +   PROPERTIES
 +-    IMPORTED_LOCATION ${CORE_PATH}/lib/linux/x86_64/libLive2DCubismCore.a
 ++    IMPORTED_LOCATION ${CORE_PATH}/lib/experimental/rpi/libLive2DCubismCore.a
 +     INTERFACE_INCLUDE_DIRECTORIES ${CORE_PATH}/include
 + )
 + 
  @@ -64,6 +64,11 @@ target_link_libraries(Framework Live2DCu
   # Find opengl libraries.
   find_package(OpenGL REQUIRED)