Use Docker since Travis host OS is super old

.travis.yml

 language: cpp
-addons:
-  apt:
-    sources:
-      - neon
-      - sourceline: 'deb http://archive.neon.kde.org/user xenial main'
-        key_url: 'http://archive.neon.kde.org/public.key'
-    packages:
-      - cmake
-      - extra-cmake-modules
-      - gettext
-      - kio-dev
-      - libatasmart-dev
-      - libboost-python-dev
-      - libkf5config-dev
-      - libkf5coreaddons-dev
-      - libkf5i18n-dev
-      - libkf5iconthemes-dev
-      - libkf5parts-dev
-      - libkf5service-dev
-      - libkf5solid-dev
-      - libkpmcore-dev
-      - libparted-dev
-      - libpolkit-qt5-1-dev
-      - libqt5svg5-dev
-      - libqt5webkit5-dev
-      - libyaml-cpp-dev
-      - os-prober
-      - pkg-config
-      - python3-dev
-      - qtbase5-dev
-      - qtdeclarative5-dev
-      - qttools5-dev
-      - qttools5-dev-tool
+sudo: required
+
+services:
+  - docker
+
+before_install:
+  - docker build -t calamares .
 
 script:
-  - cmake -DWEBVIEW_FORCE_WEBKIT=1 -DKDE_INSTALL_USE_QT_SYS_PATHS=ON .
-  - make
+  - docker run -v $PWD:/build calamares bash -lc "cd /build && cmake -DWEBVIEW_FORCE_WEBKIT=1 -DKDE_INSTALL_USE_QT_SYS_PATHS=ON . && make -j9"

Dockerfile

+FROM debian:testing
+RUN apt-get update && apt-get -y install build-essential cmake extra-cmake-modules gettext kio-dev libatasmart-dev libboost-python-dev libkf5config-dev libkf5coreaddons-dev libkf5i18n-dev libkf5iconthemes-dev libkf5parts-dev libkf5service-dev libkf5solid-dev libkpmcore4-dev libparted-dev libpolkit-qt5-1-dev libqt5svg5-dev libqt5webkit5-dev libyaml-cpp-dev os-prober pkg-config python3-dev qtbase5-dev qtdeclarative5-dev qttools5-dev qttools5-dev-tools