[Cmake] BUILD_SHARED_LIBRARIES

[Brad King]

Hello,

The BUILD_SHARED_LIBRARIES command has been deprecated.  It has been
removed from the top level CMakeLists.txt files in Insight and VTK-new.  
The command will be removed in about a week.  For now it generates an
error stating that it has been deprecated.

Instead, CMake now always generates the boolean BUILD_SHARED_LIBS cache
entry, just as EXECUTABLE_OUTPUT_PATH and LIBRARY_OUTPUT_PATH are always
entered into the cache.

-Brad