layers: MR149, Cleanup CMD_NODE use in draw_state

Move pCmds vector<CMD_NODE*> to be cmds vector<CMD_NODE> instead. This simplifies
cleanup of the data structure as we don't have to manage the ptr new/delete lifecycle.
diff --git a/layers/draw_state.h b/layers/draw_state.h
index e2e8aeb..cbd9a08 100755
--- a/layers/draw_state.h
+++ b/layers/draw_state.h
@@ -485,7 +485,7 @@
     CB_STATE                     state;  // Track cmd buffer update state
     uint64_t                     submitCount; // Number of times CB has been submitted
     CBStatusFlags                status; // Track status of various bindings on cmd buffer
-    vector<CMD_NODE*>            pCmds;
+    vector<CMD_NODE>             cmds; // vector of commands bound to this command buffer
     // Currently storing "lastBound" objects on per-CB basis
     //  long-term may want to create caches of "lastBound" states and could have
     //  each individual CMD_NODE referencing its own "lastBound" state