Add pylint checker to the project (#1602)

* Added 'pylint' to dependencies
 * Added pylint config file
 * Added to travis CI as an allow failure job
   (until all of the warnings are fixed)
 * Added to 'run-test.py'

Related issue: #1600

JerryScript-DCO-1.0-Signed-off-by: László Langó llango.u-szeged@partner.samsung.com

tools/check-pylint.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+# Copyright JS Foundation and other contributors, http://js.foundation
+#
+# 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.
+
+find -name "*.py" \
+    | xargs pylint --rcfile=tools/pylint/pylintrc