Alphabetize DXSearch methods.
Java: refactor to extract code for paginating through queries.
Java: find* result pages are forward compatible with new fields.

More specifically the inner "Entry" classes (corresponding to each
individual result) need @JsonIgnoreProperties(ignoreUnknown) so that
they ignore new fields that might be added in the future. Previously,
only the surrounding class (corresponding to the entire result packet)
had this set.

Also, minor docstring fixes.