Fix warnings related to Vector3::operator= and remove -Wno-deprecated-copy suppression

# Conflicts:
#	cmake/compiler/clang/settings.cmake

cmake/compiler/gcc/settings.cmake

@@ -33,10 +33,6 @@ if( WITH_WARNINGS )
       -Wfatal-errors
       -Woverloaded-virtual)
 
-  target_compile_options(trinity-warning-interface
-    INTERFACE
-      -Wno-deprecated-copy) # warning in g3d
-
   message(STATUS "GCC: All warnings enabled")
 endif()