single slicer instance

check for other instances during startup
send message with command line arguments if found and terminate
listen for those messages and load objects from paths in messages from them

CMakeLists.txt

@@ -160,6 +160,9 @@ if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
     # Boost on Raspberry-Pi does not link to pthreads.
     set(THREADS_PREFER_PTHREAD_FLAG ON)
     find_package(Threads REQUIRED)
+
+    find_package(DBus REQUIRED)
+    include_directories(${DBUS_INCLUDE_DIRS})
 endif()
 
 if (CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUXX)