Add support for Java format strings in the Formatter syntax.

Add support for Java format strings in the Formatter syntax.

* gettext-tools/src/message.h (format_type): Add format_java_printf.
(NFORMATS): Increment.
* gettext-tools/src/message.c (format_language, format_language_pretty): Add
entry for format_java_printf.
* gettext-tools/src/format.h (formatstring_java_printf): New declaration.
* gettext-tools/src/format-java.c: Update comments.
* gettext-tools/src/format-java-printf.c: New file.
* gettext-tools/src/format.c (formatstring_parsers): Add entry for
format_java_printf.
* gettext-tools/src/x-java.h (SCANNERS_JAVA): Use formatstring_java_printf.
* gettext-tools/src/x-java.c (init_flag_table_java): Add entries relevant to
format strings in Formatter syntax.
* gettext-tools/src/xgettext.c (xgettext_record_flag): Add support for
format_java_printf.
* gettext-tools/src/FILES: Add format-java-printf.c.
* gettext-tools/src/Makefile.am (FORMAT_SOURCE): Add format-java-printf.c.
* gettext-tools/woe32dll/gettextsrc-exports.c: Export formatstring_java_printf.
* gettext-tools/libgettextpo/Makefile.am (libgettextpo_la_AUXSOURCES): Likewise.
* gettext-tools/tests/xgettext-6 (xg-test6.java): Add test for recognition of
format strings in Formatter syntax.
* gettext-tools/tests/format-java-printf-1: New file.
* gettext-tools/tests/format-java-printf-2: New file.
* gettext-tools/tests/Makefile.am (TESTS): Add them.
* gettext-tools/tests/lang-java: Add two uses of String.format to the program.
* gettext-tools/doc/gettext.texi (PO Files): Document java-printf-format and
no-java-printf-format.
(java-format): Describe both kinds of format strings. Update URLs.
(Java): Mention the second kind of format string as well.
* NEWS: Mention the improvement.