There are now 3 kinds of nodes: Eprim : primitive
nodes, Enode: nodes with memory, Efun: nodes
without memory.
Typing now sets correct eq_statefull and b_statefull
for equations and blocks. Resets are only added
when a node with memory is called.
The calling convention is the generated code needs
to be modified so that we can remove the context
for nodes without memory.
