revert of conan stuff

Author: Hana Dusíková

.travis.yml

@@ -28,9 +28,11 @@ matrix:
     services:
       - docker
     env:
-      - COMPILER=g++
+      - COMPILER=g++-8
       - CONAN_GCC_VERSIONS=8
-      - CONAN_DOCKER_IMAGE=conanio/gcc8
+      - CONAN_DOCKER_IMAGE=lasote/conangcc8
+    install:
+       - pip install -U conan conan-package-tools
     script:
       - python .conan/build.py