Fix function name

[OssiPesonen]

Took a liking to this project and I'm gonna implement it on an open source project.

Noticed a small typo here:
https://github.com/respectTheCode/node-caspar-cg/blob/master/lib/data.js#L45

Fix to dataObJectToXml. Thanks!

[happyt]

Or dataObjectToXml ? Lower case j