Parsers in rival-split to example?

[alansaid]

Comment:
The parsers in net.recommenders.rival.split.parser should be moved to examples.
The reason for this is that they all correlate to an example dataset. There is also a parser in net.recommenders.rival.evaluation.parser which seems to be the same kind of parser as the other ones.
If not moved to examples, the parsers should at least be moved to one location.

Most of the parsers should be replaceable by net.recommenders.rival.core.UIPParser (user-item-preference parser) which uses Commons CSV and allows the parser to be configured to whatever dataset is used by the "example" code.