[torquedev] Rework of RESMOM main loop

[Steve Snelgrove]

I have just commited in trunk (2.3) a rework of the RESMOM main loop.
This is revision 1859.  I was having a very hard time understanding the
overall workings of this code and this was an attempt to get the code
to a point where I could reason about it.  I tried to be very conservative
and only do instantiation and factoring without doing statement
reordering.

I hope that this is acceptable and if not, just revert it.