remove redundant lines from .travis.yml for dwyl/learn-travis#31

.travis.yml

@@ -15,7 +15,7 @@ cache:
     - elm-stuff/build-artifacts
     - elm-stuff/packages
     - tests/elm-stuff/build-artifacts # elm-test init creates a "tests/" dir
-    - tests/elm-stuff/packages
+    - tests/elm-stuff/packages        # cache files that haven't changed
     - sysconfcpus
     - $HOME/.npm # https://stackoverflow.com/a/42523517/1148249
 
@@ -24,7 +24,7 @@ before_install:
   - if [ ${TRAVIS_OS_NAME} == "osx" ];
     then brew update; brew install nvm; mkdir ~/.nvm; export NVM_DIR=~/.nvm; source $(brew --prefix nvm)/nvm.sh;
     fi
-  - | # epic build time improvement - 10 mins >> 5 sec! see https://git.io/vQcqz
+  - | # build time improvement - 10 mins >> 5 sec! see https://git.io/vQcqz
     if [ ! -d sysconfcpus/bin ];
     then
       git clone https://github.com/obmarg/libsysconfcpus.git;
@@ -41,15 +41,9 @@ install: # install specific versions of elm & elm-test
   - printf "#\041/bin/bash\n\necho \"Running elm-make with sysconfcpus -n 2\"\n\n$TRAVIS_BUILD_DIR/sysconfcpus/bin/sysconfcpus -n 2 elm-make-old \"\$@\"" > $(npm config get prefix)/bin/elm-make
   - chmod +x $(npm config get prefix)/bin/elm-make
   - travis_retry elm package install --yes # install main project dependencies
-  # - cd tests                  # change into /test directory to install more deps
-  # - elm package install --yes # install test dependencies
-  # - cd ..                     # change back into root project directory
   - pwd
 
-# before_script:     # print some useful debug info
-
 
 script:
   - elm-format --validate PhotoGroove.elm # lint / format-check main file
-  # - elm-make PhotoGroove.elm --output elm.js --warn # attempt elm-make
   - elm-test --verbose                    # run the tests!