Add node script to report coverage

package.json

@@ -20,6 +20,7 @@
     "test": "run-s clean test:commonjs",
     "test:umd": "./scripts/test_umd.sh",
     "test:coverage": "nyc npm run test --all",
+    "report_test_coverage": "nyc report --reporter=text-lcov | coveralls",
     "update_contracts": "for i in ${npm_package_config_artifacts}; do copyfiles -u 4 ../contracts/build/contracts/$i.json ../0x.js/src/artifacts; done;",
     "testrpc": "testrpc -p 8545 --networkId 50 -m \"${npm_package_config_mnemonic}\"",
     "docs:json": "typedoc --excludePrivate --excludeExternals --target ES5 --json docs/index.json .",