ossim stream hierarchy has triangle inheritance

[dburken]

This pertains to all ossim streams:

ossimStreamBase derives from std::ios. ossimIStream derives from std::ios and ossimProtocolStream which dervives from ossimStreamBase which derives from std::ios; hence the inheritance triange.

[dburken]

Made ossimStreamBase derive from ossimReferenced.

Made all ossim streams derive from ossimStreamBase and their respective std stream.

Changed stream factory to return an ossimIFStream.

Updated all callers of stream factory.

Files: ossim/include/ossim/elevation/ossimSrtmHandler.h ossim/include/ossim/elevation/ossimGeneralRasterElevHandler.h ossim/include/ossim/base/ossimIoStream.h ossim/include/ossim/base/ossimStreamFactory.h ossim/include/ossim/base/ossimStreamBase.h ossim/include/ossim/base/ossimStreamFactoryBase.h ossim/include/ossim/base/ossimGzStream.h ossim/include/ossim/base/ossimStreamFactoryRegistry.h ossim/include/ossim/imaging/ossimGeneralRasterTileSource.h ossim/include/ossim/imaging/ossimImageFileWriter.h ossim/src/ossim/elevation/ossimSrtmHandler.cpp ossim/src/ossim/elevation/ossimGeneralRasterElevHandler.cpp ossim/src/ossim/elevation/ossimSrtmFactory.cpp ossim/src/ossim/base/ossimStreamBase.cpp ossim/src/ossim/base/ossimStreamFactory.cpp ossim/src/ossim/base/ossimIoStream.cpp ossim/src/ossim/base/ossimGzStream.cpp ossim/src/ossim/base/ossimStreamFactoryRegistry.cpp

[gpotts]

Fixed ossimSrtmFilename and missing virtual in ossimImageFileWriter that takes an istream& that wasn't in the source file