Use mocha tap reporter only for Travis CI

.travis.yml

@@ -1,7 +1,7 @@
 language: node_js
 node_js:
   - "0.10"
-script: npm test --coverage
+script: MOCHA_REPORTER=tap npm test --coverage
 after_success:
 - npm run coveralls
 notifications:
@@ -10,4 +10,4 @@ notifications:
       - https://webhooks.gitter.im/e/d1ec4245f90231619d30
     on_success: change  # options: [always|never|change] default: always
     on_failure: always  # options: [always|never|change] default: always
-    on_start: false     # default: false
+    on_start: false     # default: false

package.json

@@ -50,7 +50,7 @@
   "scripts": {
     "build": "node_modules/.bin/gulp",
     "pretest": "node_modules/.bin/gulp concat-sjcl",
-    "test": "./node_modules/.bin/istanbul test -x build/sjcl.js -x src/js/jsbn/* ./node_modules/mocha/bin/_mocha -- --reporter tap test/*-test.js",
+    "test": "./node_modules/.bin/istanbul test -x build/sjcl.js -x src/js/jsbn/* ./node_modules/mocha/bin/_mocha -- --reporter ${MOCHA_REPORTER:=spec} test/*-test.js",
     "coveralls": "cat ./coverage/lcov.info | ./node_modules/.bin/coveralls",
     "lint": "eslint --reset -c eslint.json src/js/ripple/*.js",
     "perf": "./scripts/perf_test.sh"