Fix tests of TextDelimited quoting behavior.

It seems that a faulty unit test slipped in the `more-taps` test suite.
The test was missing an `=>` and thus always successful.

Fixing the test though causes it to fail, as the behaviour of TextDelimited has changed
to match the [CSV spec](http://tools.ietf.org/html/rfc4180) more closely. This (unexpected) behavior has been dicussed in #150.

This patch adjusts the tests to match the new behavior.

Note though that the way TextDelimited writes fields is still not in compliance with the specification,
this is documented and tested as well.

Inspection of this patch by @Quantisan is probably advisable.