Adds rgdal system library dependecies to travis configuration

.travis.yml

@@ -1,15 +1,19 @@
-language: c
+language: r
+dist: trusty
+sudo: required
+cache: packages
+
 before_install:
-- curl -OL http://raw.github.com/craigcitro/r-travis/master/scripts/travis-tool.sh
-- chmod 755 ./travis-tool.sh
-- "./travis-tool.sh bootstrap"
-install:
-- "./travis-tool.sh install_deps"
-script: "./travis-tool.sh run_tests"
-on_failure:
-- "./travis-tool.sh dump_logs"
+  - sudo apt-get install -y libproj-dev libgdal-dev
+
+compiler:
+  - clang
+
+warnings_are_errors: false
+
 after_success:
   - Rscript -e 'covr::codecov()'
+
 notifications:
   email:
     on_success: change