Refactor for gcc-4.0: nested classes do not inherit 'friend' status in earlier standard

Input/OutputPartData now structs not classes
templated getInputPart and getOutputPart moved to MultiPartInputFile and MultiPartOutputFile rather than their respective ::Data members
create*Part functions in MultiPartInputFile and MultiPartOutputFile removed: internally using getInput/OutputPart<> instead
Extraneous displayWindow call removed from writeHeadersToFile()
Switch #include <Imf...> to #include "Imf..." in most .cpp files
TileOffsets::isValidTile made public not private
TileOffsets::getOffsets() made const public not non-const private