use firefox when running karma in travis

.travis.yml

@@ -4,9 +4,8 @@ node_js:
 before_install:
   - npm install -g bower
   - npm install -g grunt-cli
-  - "export CHROME_BIN=/usr/bin/chromium-browser"
-  - "export DISPLAY=:99.0"
-  - "sh -e /etc/init.d/xvfb start"
+  - export DISPLAY=:99.0
+  - sh -e /etc/init.d/xvfb start
 install:
   - npm install
   - bower install

karma.conf.js

@@ -99,7 +99,7 @@ module.exports = function(config) {
 
     // start these browsers
     // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
-    browsers: ['Firefox'],
+    browsers: ['Chrome'],
 
 
     // Continuous Integration mode

package.json

@@ -24,8 +24,7 @@
     "setup-shell": "node shell/scripts/download-atom-shell.js",
     "start": "node server.js",
     "coverage": "./node_modules/.bin/istanbul cover ./node_modules/.bin/_mocha -- --reporter spec test",
-    "test-original": "./node_modules/.bin/istanbul cover ./node_modules/mocha/bin/_mocha --report lcovonly -- -R spec && cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js",
-    "test": "./node_modules/karma/bin/karma start --browsers Firefox --single-run --captureTimeout 10000",
+    "test": "./node_modules/.bin/istanbul cover ./node_modules/mocha/bin/_mocha --report lcovonly -- -R spec && cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js && ./node_modules/karma/bin/karma start --browsers Firefox --single-run",
     "dist": "node shell/scripts/dist.js",
     "sign": "gpg -u 1112CFA1 --output browser-extensions/firefox/copay.xpi.sig --detach-sig browser-extensions/firefox/copay.xpi; gpg -u 1112CFA1 --output browser-extensions/chrome/copay-chrome-extension.zip.sig --detach-sig browser-extensions/chrome/copay-chrome-extension.zip",
     "verify": "gpg --verify browser-extensions/firefox/copay.xpi.sig browser-extensions/firefox/copay.xpi; gpg --verify browser-extensions/chrome/copay-chrome-extension.zip.sig browser-extensions/chrome/copay-chrome-extension.zip"