Despgraph: Keep track of per-component visibility

The idea of those flags is to avoid evaluation of operations
which are not needed to bring visible objects to an up to date
state.

Previously, dependency graph attempted to do combine those
into an ID level flag. In practice it proved to be rather
tricky, since there could be dependency cycles on ID level
which will not exist on component level.

source/blender/depsgraph/intern/nodes/deg_node_component.cc

@@ -124,7 +124,8 @@ static void comp_node_hash_value_free(void *value_v)
 
 ComponentDepsNode::ComponentDepsNode() :
     entry_operation(NULL),
-    exit_operation(NULL)
+    exit_operation(NULL),
+    affects_directly_visible(false)
 {
 	operations_map = BLI_ghash_new(comp_node_hash_key,
 	                               comp_node_hash_key_cmp,