app, plug-ins, libgimp*: clean out all remaining trailing spaces/tabs.

Rather than just discovering them by chance, a simple grep and some
search and replace are much more efficient! :-)
Cleaning only done on C and automake files.

plug-ins/imagemap/imap_cern_parse.h

@@ -1,19 +1,19 @@
 /* A Bison parser, made by GNU Bison 2.6.1.  */
 
 /* Bison interface for Yacc-like parsers in C
-   
+
       Copyright (C) 1984, 1989-1990, 2000-2012 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
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
-   
+
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
-   
+
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
@@ -26,7 +26,7 @@
    special exception, which will cause the skeleton and the resulting
    Bison output files to be licensed under the GNU General Public
    License without this special exception.
-   
+
    This special exception was added by the Free Software Foundation in
    version 2.2 of Bison.  */