Get the final string distance, which will be based on the distances learned by the
inner learners, as well as the combination scheme learned by comboSetAnswer, comboTrain,
and etc.
A StringWrapper that stores a version of the string
that has been either (a) split into a number of distinct fields,
or (b) duplicated k times, so that k different StringDistance's
can preprocess it, of (b) both of the above.
Something that implements some of the functionality of Java's
string class, but which is a non-final class, and hence can also
cache additional information to facilitate later processing.