Compile issues with Qt5 on Mac and Windows

We have built CTK on MacOSX 10.8/clang, Windows8/VS 2013 and Ubuntu 14.04/gcc. The fixes in this pull request were required to make it build. We used the cmake command:

> cmake ../CTK -DCTK_QT_VERSION:STRING=5 -DCTK_ENABLE_PluginFramework:BOOL=ON -DCTK_ENABLE_DICOM:BOOL=ON -DCTK_BUILD_EXAMPLES:BOOL=ON

The DICOM examples still don't run, due to linker problems. I'll post about this issue on the developer list.