ci: .travis.yml: Refactor, add working focal build.

The existing targets for precise and osx breaks, both on dependencies.
Seems to be about the 'rosdep install'  command in the Makefile(?),
which is beyond my current scope.

Add a new target for Ubuntu focal which works after refactoring the
.travis.yml file.

Gbp-Pq: Name 0011-ci-.travis.yml-Refactor-add-working-focal-build.patch

.travis.yml

@@ -1,10 +1,32 @@
-os:
-  - linux
-  - osx
 language: cpp
-install:
-  - make install_deps
-  - source setup.bash
-script:
-  - mkdir build && cd build && cmake .. -DPYTHON_EXECUTABLE=$(which python2) && make && make tests && make run_tests
-  - catkin_test_results .
+matrix:
+  include:
+    - os:  linux
+      dist: focal
+      compiler: gcc
+      script:
+        - sudo apt update
+        - >
+          sudo apt install build-essential
+          catkin cmake doxygen graphviz libboost-dev
+        - mkdir build && cd build
+        - cmake ..
+        - make
+        - make run_tests
+
+    - os:  linux
+      dist: precise
+      compiler: gcc
+      install:
+        - make install_deps
+        - source setup.bash
+      script:
+        - make && make test
+
+    - os: osx
+      compiler: clang
+      install:
+        - make install_deps
+        - source setup.bash
+      script:
+        - make && make test