Add python-future by using python requirements file

tools/check_python_dependencies.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+#
+# Copyright 2018 Espressif Systems (Shanghai) PTE LTD
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import sys
+try:
+    import pkg_resources
+except:
+    print('pkg_resources cannot be imported probably because the pip package is not installed and/or using a '
+          'legacy Python interpreter. Please refer to the Get Started section of the ESP-IDF Programming Guide for '
+           'setting up the required packages.')
+    sys.exit(1)
+
+req_file = '{}/requirements.txt'.format(os.getenv("IDF_PATH"))
+
+if __name__ == "__main__":
+    not_satisfied = []
+    with open(req_file) as f:
+        for line in f:
+            line = line.strip()
+            try:
+                pkg_resources.require(line)
+            except:
+                not_satisfied.append(line)
+
+    if len(not_satisfied) > 0:
+        print('The following Python requirements are not satisfied:')
+        for requirement in not_satisfied:
+            print(requirement)
+        print('Please run "{} -m pip install -r {}" for resolving the issue.'.format(sys.executable, req_file))
+        sys.exit(1)
+
+    print('Python requirements are satisfied.')