* casereader-translator.c (struct casereader_translator): Change

* casereader-translator.c (struct casereader_translator): Change
input case parameter of translate member function from const
struct ccase * to struct ccase *.
(casereader_create_translator): Ditto, for translate parameter.

* casewriter-translator.c (struct casewriter_translator): Ditto.
(casewriter_create_translator): Ditto.

* get.c (get_translate_case): Change input case parameter from
const struct ccase * to struct ccase *, to match change in
casereader and casewriter translators.  Destroy input case, to fix
memory leak.