tweak ci script

build/ci.sh

@@ -4,7 +4,13 @@ npm run flow
 npm run test:cover
 npm run test:e2e -- --env phantomjs
 npm run test:ssr
-if [ -z "$CI_PULL_REQUEST" ]; then
+
+# report coverage stats for non-PRs
+if [[ -z $CI_PULL_REQUEST ]]; then
   cat ./coverage/lcov.info | ./node_modules/.bin/codecov
+fi
+
+# run full browser suites on saucelabs for master branch
+if [[ $CIRCLE_BRANCH = master ]]; then
   npm run test:sauce
 fi