add tools for PaddleLite op check

tools/check_for_lite.py

+import urllib
+import sys
+from paddle.fluid.framework import Program
+
+ops_h = "https://raw.githubusercontent.com/PaddlePaddle/Paddle-Lite/develop/lite/api/_paddle_use_ops.h"
+try:
+    fetch = urllib.urlretrieve(ops_h, "./_paddle_use_ops.h")
+except:
+    fetch = urllib.request.urlretrieve(ops_h, "./_paddle_use_ops.h")
+
+ops = list()
+with open("./_paddle_use_ops.h") as f:
+    for line in f:
+        if "USE_LITE_OP" in line:
+            op = line.strip().split('(')[1].split(')')[0]
+            ops.append(op)
+
+model_file = sys.argv[1]
+with open(model_file, 'rb') as f:
+    program = Program.parse_from_string(f.read())
+
+unsupported_ops = set()
+for op in program.blocks[0].ops:
+    if op.type not in ops:
+        unsupported_ops.add(op.type)
+
+nums = len(unsupported_ops)
+if len(unsupported_ops) > 0:
+    print("========= {} OPs are not supported in Paddle-Lite=========".format(
+        nums))
+    for op in unsupported_ops:
+        print("========= {} ========".format(op))
+else:
+    print("\n========== Good News! ========")
+    print("Good! All ops in this model are supported in Paddle-Lite!\n")