Remove travis docs build.

.travis.yml

@@ -1,27 +0,0 @@
-sudo: false
-
-before_install:
- - cd ${TMPDIR-/tmp}
- - wget -q http://doxygen.nl/files/doxygen-1.9.0.src.tar.gz
- - tar -xzvf doxygen-1.9.0.src.tar.gz
- - mkdir doxygen_build
- - cd doxygen_build
- - cmake ../doxygen-1.9.0/
- - make
- - export PATH="${TMPDIR-/tmp}/doxygen_build/bin:$PATH"
- - cd ${TRAVIS_BUILD_DIR}
- 
-branches:
-  only:
-    - master
-
-script:
-  - doxygen ./docs/Doxyfile
-
-deploy:
-  provider: pages
-  skip_cleanup: true
-  local_dir: docs/html
-  github_token: $GH_REPO_TOKEN
-  on:
-    branch: master