add make check_format to check astyle code formatting

Tools/check_code_style.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+set -eu
+failed=0
+for fn in $(find . -path './src/lib/uavcan' -prune -o \
+                   -path './NuttX' -prune -o \
+                   -path './Build' -prune -o \
+                   -path './mavlink' -prune -o \
+                   -path './unittests/gtest' -prune -o \
+                   -name '*.c' -o -name '*.cpp' -o -name '*.hpp' -o -name '*.h' -type f); do
+  if [ -f "$fn" ];
+  then
+    ./Tools/fix_code_style.sh --quiet < $fn > $fn.pretty
+    diffsize=$(diff -y --suppress-common-lines $fn $fn.pretty | wc -l)
+    rm -f $fn.pretty
+    if [ $diffsize -ne 0 ]; then
+      failed=1
+      echo $diffsize $fn
+    fi
+  fi
+done
+
+if [ $failed -eq 0 ]; then
+    echo "Format checks passed"
+    exit 0
+else
+    echo "Format checks failed; please run ./Tools/fix_code_style.sh on each file"
+    exit 1
+fi