Add flag for enabling applications (on by default).

CMakeLists.txt

@@ -108,6 +108,7 @@ cmake_dependent_option(
   SMTK_ENABLE_PYTHON_WRAPPING OFF)
 mark_as_advanced(SMTK_INSTALL_PYTHON_TO_SITE_PACKAGES)
 option(SMTK_ENABLE_QT_SUPPORT "Build Qt GUI" OFF)
+cmake_dependent_option(SMTK_ENABLE_APPLICATIONS "Build Qt-enabled applications" ON SMTK_ENABLE_QT_SUPPORT OFF)
 option(SMTK_ENABLE_VTK_SUPPORT "Build VTK component" ON)
 option(SMTK_ENABLE_REMUS_SUPPORT "Build Remus components" OFF)
 cmake_dependent_option(SMTK_ENABLE_PARAVIEW_SUPPORT "Build paraview plugins for model sessions" OFF
@@ -627,7 +628,7 @@ endif ()
 add_subdirectory(smtk)
 
 # Build SMTK Applications
-if(SMTK_ENABLE_QT_SUPPORT)
+if(SMTK_ENABLE_APPLICATIONS)
   add_subdirectory(applications)
 endif()