Raise UnexpectedFormatException when Title is not set in Science Plus reference

[Paldana99]

@E-Bara @jdp1ps

In the validate_reference decorator. I added a UnexpectedFormatException raise if there are any fields failed. That way, the abstract_harvester can handle the error, and continue to convert other documents.

[Paldana99]

After discussion, I raise the UnexpectedFormatException at the Science Plus converter.