Added test command for Windows support

Use `npm run test:win` to run tests on Windows. Fixes parse-community#323.
Variables like `$COVERAGE_OPTION` are not supported in Windows.

package.json

@@ -59,6 +59,7 @@
     "build": "./node_modules/.bin/babel src/ -d lib/",
     "pretest": "cross-env MONGODB_VERSION=${MONGODB_VERSION:=3.0.8} ./node_modules/.bin/mongodb-runner start",
     "test": "cross-env NODE_ENV=test TESTING=1 ./node_modules/.bin/babel-node $COVERAGE_OPTION ./node_modules/jasmine/bin/jasmine.js",
+    "test:win": "npm run pretest && cross-env NODE_ENV=test TESTING=1 ./node_modules/.bin/babel-node ./node_modules/babel-istanbul/lib/cli.js cover -x **/spec/** ./node_modules/jasmine/bin/jasmine.js && npm run posttest",
     "posttest": "./node_modules/.bin/mongodb-runner stop",
     "coverage": "cross-env COVERAGE_OPTION='./node_modules/babel-istanbul/lib/cli.js cover -x **/spec/**' npm test",
     "start": "node ./bin/parse-server",