Add example test script

tests/test_examples.sh

@@ -0,0 +1,10 @@
+#! /bin/bash
+
+for example in $(find $1 -maxdepth 1 -name "*.py")
+do
+    echo "test:" $example
+    export DISPLAY= && python $example --fast_dev_run 1
+    if [[ $? -ne 0 ]]; then
+        exit 1
+    fi
+done