fix building packages on travis-docker (#3441)

* add docker compilation to travis

add new matrix entry in .travis.yml for compiling on 18.04
add Dockerfile in .ci to build ubuntu 18.04 inside docker
remove release entry for uvuntu 16.04 to not conflict
refactor .travis.yml
refactor travis-comile.sh
merge travis-dependencies.sh into the travis.yml
remove travis-dependencies.sh

* enable debugging on travis-compile.sh

* set ubuntu16 buildtype to "Debug"

set buildtype Debug for as requirement for "test"
add --debug and --release flags to travis-compile.sh

* make output prettier

edit the format warning message and clangify.sh output

* fix clangify.sh

fix --cf-version flag
fix directory argument parsing
add directory parsing details to --help
add examples to --help

* test making packages

move dockerfile for bionic to make room for possibly other files
add missing file dependency
set macos brew to use protobuf --without-python@2

* remove test

* rm old Dockerfile

.ci/UbuntuBionic/Dockerfile

@@ -4,6 +4,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         bc \
         build-essential \
         clang-format \
+        file \
         g++ \
         git \
         cmake \

.travis.yml

@@ -8,14 +8,14 @@ matrix:
   - name: Ubuntu Bionic (Debug)
     if: tag IS NOT present
     services: docker
-    before_install: docker build -t img .ci
+    before_install: docker build -t img .ci/UbuntuBionic
     script: docker run --mount "type=bind,source=$(pwd),target=/src" -w="/src" img
           bash .ci/travis-compile.sh --server --debug
   - name: Ubuntu Bionic (Release)
     if: (branch = master AND NOT type = pull_request) OR tag IS present
     services: docker
-    script: docker build -t img .ci &&
-        docker run --mount "type=bind,source=$(pwd),target=/src" -w="/src" img
+    before_install: docker build -t img .ci/UbuntuBionic
+    script: docker run --mount "type=bind,source=$(pwd),target=/src" -w="/src" img
           bash .ci/travis-compile.sh --server --package --release
 
   #Ubuntu Xenial (Debug only)
@@ -44,11 +44,9 @@ matrix:
     os: osx
     osx_image: xcode8
     before_install:
-      - brew update
       - brew update
       - brew install ccache
-      - brew unlink python # protobuf python2 install requires this link to be removed
-      - brew install protobuf
+      - brew install protobuf --without-python@2
       - brew install qt
     script: bash ./.ci/travis-compile.sh --server --install --debug
   - name: macOS (Release)
@@ -56,11 +54,9 @@ matrix:
     os: osx
     osx_image: xcode8
     before_install:
-      - brew update
       - brew update
       - brew install ccache
-      - brew unlink python # protobuf python2 install requires this link to be removed
-      - brew install protobuf
+      - brew install protobuf --without-python@2
       - brew install qt
     script: bash ./.ci/travis-compile.sh --server --package --release