Previous value as last change in Ram Search (Perhaps Ram Watch as well)

I think it would be useful to have a last change option for "Define Previous 
Value As". The default option updates the previous value every frame. The only 
real use of this mode, from my experience, is to check if a value in the 
previous frame is equal to the value in the current frame or not. Regrettably, 
if I want to see if the last change to the value was positive or negative, I 
better hope that the change happened this frame; if it happened in the last 
one, the previous value will now equal the current value, making the comparison 
useless. The only drawback to this mode I can think of is that the (Not) Equal 
To comparison operator would be mostly useless, but if the previous value 
defaults to the current value, then these operators can be used to check if the 
value has changed since the option has been selected. I think this option would 
be very useful if I'd like to find an X position without having to pause while 
moving right in order to check for values that are greater than their previous 
value; consider also movement that doesn't occur every frame / lag frames!

Original issue reported on code.google.com by brandman...@gmail.com on 8 Jun 2012 at 6:38

2000DTM / bizhawk

Previous value as last change in Ram Search (Perhaps Ram Watch as well) #73