Conan build added (#160).

.travis.yml

     - env: COMPILER=clang-7
     - env: COMPILER=clang-6
     - env: COMPILER=clang-5
+    - env: CONAN_GCC_VERSIONS=9 CONAN_DOCKER_IMAGE=conanio/gcc9
 
 
 before_install:
-  - docker pull ${DOCKER_IMG}/${COMPILER}:stable
+  - if [[ -v COMPILER ]]; then docker pull ${DOCKER_IMG}/${COMPILER}:stable; fi
 
 script:
-  - docker run -v ${PWD}:/mnt -it ${DOCKER_IMG}/${COMPILER} /bin/bash -c "cd /mnt; script/ci_build.sh"
+  - if [[ -v COMPILER ]]; then docker run -v ${PWD}:/mnt -it ${DOCKER_IMG}/${COMPILER} /bin/bash -c "cd /mnt; script/ci_build.sh"; fi
+  - if [[ -v CONAN_DOCKER_IMAGE ]]; then script/conan_build.sh; fi

build.py

+from cpt.packager import ConanMultiPackager
+
+if __name__ == "__main__":
+    builder = ConanMultiPackager()
+    builder.add_common_builds()
+    builder.run()

script/conan_build.sh

+#!/bin/bash
+
+set -ex
+
+pip install -U conan conan_package_tools
+python build.py