[Users] MoL_InitialCopy

[Steven R. Brandt]

So I'm curious about why Cactus/MoL does things the way it does.
For the sake of this example, consider that we are evolving the variable
B and we compute B_RHS during the evolution.

First, we fill in initial data. B = something.
Second, at the start of the iteration loop, we rotate time levels. B --> 
B_p, B --> invalid
Third, MoL_InitialCopy copies the previous time level to the current. 
B_p --> B
Fourth, we evolve. B_RHS = Foo(B)

MoL_InitialCopy seems to be a wasted step. It would not be needed if
(1) time levels were rotated at the end of the iteration loop, or
(2) we computed B_RHS = Foo(B_p)

Am I missing something? Why do we do things that way?

--Steve