Updated babel-core dev dependencies

[tylermadison]

This fixes the build error on a fresh install:

ERROR in ./src/client.js
[0] Module build failed: Error: ~/react-isomorphic-starterkit/src/client.js: attachComments needs range information
[0]     at Object.attachComments (~/react-isomorphic-starterkit/node_modules/babel-core/node_modules/estraverse/estraverse.js:741:19)
[0]     at Object.exports.default (~/react-isomorphic-starterkit/node_modules/babel-core/lib/helpers/parse.js:80:27)
[0]     at File.parse (~/react-isomorphic-starterkit/node_modules/babel-core/lib/transformation/file/index.js:549:40)
[0]     at File.parseCode (~/react-isomorphic-starterkit/node_modules/babel-core/lib/transformation/file/index.js:658:20)
[0]     at ~/react-isomorphic-starterkit/node_modules/babel-core/lib/transformation/pipeline.js:167:12
[0]     at File.wrap (~/react-isomorphic-starterkit/node_modules/babel-core/lib/transformation/file/index.js:614:16)
[0]     at Pipeline.transform (~/react-isomorphic-starterkit/node_modules/babel-core/lib/transformation/pipeline.js:165:17)
[0]     at transpile (~/react-isomorphic-starterkit/node_modules/babel-loader/index.js:12:22)
[0]     at Object.module.exports (~/react-isomorphic-starterkit/node_modules/babel-loader/index.js:69:12)
[0]  @ multi main

[RickWong]

Thanks.