Implement custom travis_wait in order to have command output still printed on the command line

.travis.yml

@@ -57,4 +57,4 @@ matrix:
 before_script:
   - npm install -g grunt-cli
 script:
-  - travis_wait $TRAVIS_BUILD_DIR/travis.sh
+  - $TRAVIS_BUILD_DIR/travis.sh

travis.sh

@@ -33,5 +33,20 @@ elif [[ $OPENPGPJSTEST =~ ^end2end-.* ]]; then
 
   echo "Testing Configuration: ${testkey}"
   eval $capability
-  grunt saucelabs
+  grunt saucelabs &
+
+  # https://github.com/travis-ci/travis-ci/issues/4190
+  minutes=0
+  limit=30
+  while kill -0 $! >/dev/null 2>&1; do
+    echo -n -e " \b" # never leave evidences!
+
+    if [ $minutes == $limit ]; then
+      break;
+    fi
+
+    minutes=$((minutes+1))
+
+    sleep 60
+  done
 fi