Batch/multi-lingual requests

[achimr]

In each request, allow array of JSON structure instead of single substructure.

Easy for plain text requests, but not requests that involve files/URLs.

[achimr]

Comment from Yves Savourel:
I wonder about the scope of the resource ID. It is for a resource that is a source/target pair. But in many systems the model is to have an ID for a resource that has a source and zero or more targets. The target language code can easily be used to make the distinction between targets. One of the reasons for this is that potentially quite a few metadata redundant when using several pairs.Examples of such model are for instance the LingoTek API: http://devzone.lingotek.com/#/api-explorer, or the Transifex API: http://docs.transifex.com/developer/api/. I'm just curious about advantages the current model of the bilingual resource brings.