dojson: original blob passed to rules

[kaplun]

• NEW Extends the dictionary being passed to dojson rules in the self argument, by adding a new special key __original_blob__ that can be used to build rules that depend on a global overview of the input. (closes #171)

Signed-off-by: Samuele Kaplun samuele.kaplun@cern.ch

[david-caro]

Though I'm not sure this is the best solution to the problem you are having, I think it's really nice to have the blob there.

[jirikuncar]

Alternative solution has been shown in https://github.com/inveniosoftware/dojson/issues/171#issuecomment-241682606