THRIFT-3515 Python 2.6 compatibility and test on CI

This closes #766
diff --git a/build/docker/centos6/Dockerfile b/build/docker/centos6/Dockerfile
new file mode 100644
index 0000000..0e571c5
--- /dev/null
+++ b/build/docker/centos6/Dockerfile
@@ -0,0 +1,49 @@
+# 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.
+
+# Apache Thrift Docker build environment for Centos 6
+#
+# This file is intended for testing old packages that are not available for
+# latest Ubuntu LTS/Debian/CentOS. Currently, it is only used for Python 2.6.
+#
+
+FROM centos:6
+MAINTAINER Apache Thrift <dev@thrift.apache.org>
+
+RUN yum install -y \
+      autoconf \
+      bison \
+      bison-devel \
+      clang \
+      flex \
+      gcc \
+      gcc-c++ \
+      git \
+      libtool \
+      m4 \
+      make \
+      perl \
+      tar \
+      python-devel \
+      python-setuptools \
+      python-twisted-web \
+      python-six \
+    && yum clean all
+
+# CMake
+RUN curl -sSL https://cmake.org/files/v3.4/cmake-3.4.1.tar.gz | tar -xz && \
+    cd cmake-3.4.1 && ./bootstrap && make -j4 && make install
+
+ENV THRIFT_ROOT /thrift
+RUN mkdir -p $THRIFT_ROOT/src
+COPY scripts $THRIFT_ROOT
+WORKDIR $THRIFT_ROOT/src