Development-to-do-list.md

@@ -20,6 +20,8 @@ Guideline for developers: whenever you plan to address an item of this TODO list
   6. add relative reference frame overall dynamics (modal element, gravity (?))
   7. add absolute/relative reference frame dynamics interface
   8. generalize inflow models for fixed wing lifting surfaces (**partially DONE**)
+  9. Untangle both the element and solver class hierarchy
+  10. Move all the private element data into global vectors; this could allow to implement 1) without writing a dump/restore method for each element and/or without resorting to CRIU
 
 ## Medium projects
   1. recover existing soft restart. See also [this GSoC project idea](https://gitlab.polimi.it/Pub/mbdyn/wikis/Google-Summer-of-Code/GSoC-Project-Ideas#cascaded-analysis)