Add initial travis build for clang-format and flake8

.clang-tidy

+Checks: -*,cppcoreguidelines-*,google-*,llvm-*,misc-*,modernize-*,performance-*

.travis.yml

+sudo: false
+language: cpp
+dist: trusty
+addons:
+  apt:
+    sources:
+      - llvm-toolchain-trusty-3.8
+    packages:
+      - clang-format-3.8
+      - clang-tidy-3.8
+before_install:
+  - wget http://www.cmake.org/files/v3.7/cmake-3.7.1-Linux-x86_64.tar.gz
+install: 
+  - tar -xf cmake-3.7.1-Linux-x86_64.tar.gz
+  - export PATH="${PWD}/cmake-3.7.1-Linux-x86_64/bin:${PATH}"
+  - pip install --user flake8
+script:
+  - cd ${TRAVIS_BUILD_DIR}
+  - scripts/travis/run-clang-format.sh
+  - ~/.local/bin/flake8 --config=flake8.cfg .
+ 

flake8.cfg

+[flake8]
+max-line-length: 80
+max-complexity: 14
+format: pylint

scripts/travis/run-clang-format.sh

+#!/usr/bin/env bash
+
+if [ -z "${TRAVIS_PULL_REQUEST_BRANCH}" ]
+then
+  echo "This is only designed to run on Pull Requests"
+  exit 1
+else
+  COMMIT_RANGE="${TRAVIS_COMMIT_RANGE/.../ }"
+fi
+
+# Run clang-format
+DIFF="$(${TRAVIS_BUILD_DIR}/scripts/developer/git/git-clang-format --diff ${COMMIT_RANGE})"
+if [ "${DIFF}" != "no modified files to format" ]
+then
+  echo "clang-format:"
+  echo "  Code format checks failed."
+  echo "  Please run clang-format (or git clang-format) on your changes"
+  echo "  before committing."
+  echo "  The following changes are suggested:"
+  echo "${DIFF}"
+  exit 1
+fi
+
+exit 0