Typo in "jsonIntend" - should be "jsonIndent"

Hi,

issue #92 introduced the "jsonIntend" flag, but I think there is a typo there.
It should be "jsonIn**d**en**t**" as in [indentation](http://en.wiktionary.org/wiki/indentation) - at least that's what the [documentation](http://i18next.com/node/pages/doc_features.html) says about it: "You can change the **Indent** of the outputted JSON File". (emphasis mine)
I changed the spelling both in the `releasenotes.md`, as well as the `filesync.js`.

Cheers,
Steffen