Rewrote the FileUtils support for data and library file paths, moving the

storage of the path lists into osgDB::Registry, and changed the data
structor from a char* to a std::deque.  Changed a names of couple of the
convinience functions in osgDB/FileUtils to better reflect the two
public FilePathList's - DataFilePathList and the LibraryFilePathList.

Added support into the osgDB::Registry::readNode/Image/Object methods
for pushing and popping the path of the current file being loaded.

src/osgPlugins/osgtgz/ReaderWriterOSGTGZ.cpp

@@ -71,7 +71,8 @@ class sgReaderWriterOSGTGZ : public osgDB::ReaderWriter
             system( command );
 
             osg::Group *grp = new osg::Group;
-            osgDB::setFilePath( dirname );
+            
+            osgDB::PushAndPopDataPath tmppath(dirname );
 
             osgDB::DirectoryContents contents = osgDB::getDirectoryContents(dirname);
             for(osgDB::DirectoryContents::iterator itr = contents.begin();