Enable babel parser plugins needed for calypso translate

[yurynix]

After upgrade to xgettext-js 2.0.0, in order to run

npm run translate

on calypso, we need those additional plugins:

'exportDefaultFrom', 'exportNamespaceFrom'

From babel-parser:

plugin	example
exportDefaultFrom	export v from "mod" ( calypso )
exportNamespaceFrom	export * as ns from "mod" ( calypso )

Testing instructions

1. Clone this repo and run git checkout update/xgettext-version
2. Clone wp-calypso master and run npm install && rm -rf ./node_modules/i18n-calypso
3. cd this repo, run npm install && npm link
4. cd wp-calypso and run npm link i18n-calypso
5. run npm run translate
6. assert it run to completion and you see "Done."

[blowery]

Fixed by #68