Add config file list of valid identifiers to be passed through exactly as they are(not prettified)

[rtaycher]

The code generation tries to guess word boundries and apply camel case and underscore case as needed.

Bobs:
    type: object
    properties:
        IPAs:
            type: array
            items: 
                ...

For instance with fields that have acronyms like IPAs will be transformed into bobs_ip_as_item and BobsIpAS

But bobs_IPAs_item and BobsIPAsItem might be preferred. Of course you can go through and remap it item by item but when the same Abbreviations occur multiple places and with numerous sub properties/items it's much either to have an optional passthrough_identifers list