Convert underscores to dashes in some %define variable names.

For now, just api.push-pull and lr.keep-unreachable-states.
Maintain old names for backward compatibility.
* NEWS (2.5): Document.
* data/c.m4 (b4_identification): Update comment.
* data/yacc.c: Update access.
* doc/bison.texinfo: Update.
* etc/bench.pl.in (bench_grammar): Update use.
* src/files.c (tr): Move to...
* src/getargs.c, src/getargs.h (tr): ... here because I can't
think of a better place to expose it.  My logic is that, for all
uses of tr so far, command-line arguments can be involved, and
getargs.h is already included.
* src/main.c (main): Update access.
* src/muscle_tab.c (muscle_percent_define_insert): Convert old
variable names to new variable names before assigning value.
* src/reader.c (reader): Update setting default.
* tests/calc.at: Update uses.
* tests/conflicts.at (Unreachable States After Conflict
Resolution): Update use.
* tests/input.at (%define enum variables): Update use.
(%define backward compatibility): New test group.
* tests/push.at: Update uses.
* tests/reduce.at: Update uses.
* tests/torture.at: Update uses.

tests/conflicts.at

@@ -1,6 +1,7 @@
 # Exercising Bison on conflicts.                         -*- Autotest -*-
 
-# Copyright (C) 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
+# Copyright (C) 2002, 2003, 2004, 2005, 2007, 2009 Free Software
+# Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -813,7 +814,7 @@ state 7
 ]])
 
 AT_DATA([[input-keep.y]],
-[[%define lr.keep_unreachable_states
+[[%define lr.keep-unreachable-states
 ]])
 AT_CHECK([[cat input.y >> input-keep.y]])