Improve overriding of options

[YPares]

For now, the overriding of options goes like this:

Yaml file data section << Command line params << Physical files (both declared in locations and added with --loc)

This might not be intuitive. Let's say we have a record with a field called "fieldA", and located under "/Settings" in the resource tree. If a settings.json file is mapped to /Settings, and the user sets --fieldA stuff on the CLI, then this value (which would look like the definitive value) will be overriden by the value read in settings.json, even if intuitively the CLI options should override everything else.

Also if I say --loc /Settings+=settings.json on the command line, then I want whatever option read from settings.json to override all the rest, even if the final option is obtained from a file (and not directly from the CLI).

This means the exact source of each field should be tracked, and that the merge of the docrecords of options should be more intelligent.