Rename "default rule" to "default reduction".

This includes changing variable names in code, changing
comments, and renaming %define lr.default_rules to %define
lr.default_reductions.
* NEWS (2.5): Update IELR documentation.
* data/bison.m4 (b4_integral_parser_tables_map): Adjust YYDEFACT
documentation.
* data/glr.c, data/lalr1.java: Sync copyright dates.
* doc/bison.texinfo (Decl Summary): Adjust lr.default_reductions
and lr.type documentation.  Make some other wording
improvements.
(Glossary): Adjust cross-references and Default Reduction
definition.
* src/lalr.c (state_lookahead_tokens_count): Adjust code.
Remove a confusing comment pointed out by Akim Demaille.
(initialize_LA): Adjust code.
* src/print-xml.c (print_reductions): Adjust code.
* src/print.c (print_reductions): Adjust code.
* src/reader.c (reader): Adjust code.
* src/tables.c (action_row): Adjust code.
(token_actions): Adjust code.
* src/tables.h: Adjust YYDEFACT documentation.
* tests/input.at (%define lr.default_rules invalid values):
Rename test group to...
(%define lr.default_reductions invalid values): ... this, and
update grammar file and expected output.
* tests/reduce.at (AT_TEST_LR_DEFAULT_RULES): Rename to...
(AT_TEST_LR_DEFAULT_REDUCTIONS): ... this, and update.

data/lalr1.java

@@ -33,7 +33,7 @@ b4_symbol_foreach([b4_symbol_no_destructor_assert])
 m4_divert_push(0)dnl
 @output(b4_parser_file_name@)@
 b4_copyright([Skeleton implementation for Bison LALR(1) parsers in Java],
-             [2007, 2008])
+             [2007, 2008, 2009])
 
 b4_percent_define_ifdef([package], [package b4_percent_define_get([package]);
 ])[/* First part of user declarations.  */