Extend follow functionality of disassembly

I couldn't think of a proper name...
This allows to press right on add/sub/addiu/move opcodes to jump to the computed value in the memory viewer. Saves a few seconds in some cases, like when a register is overwritten in an operation, but you'd like to know both the original and the new value. Or when you just want to see what a register points to without manually switching to the memory viewer and going there yourself.

Another example:
jal func
addiu a0,sp,1Ch

Pressing right while the delay slot is highlighted would position the memory view to sp+1Ch.

Also changes a function call I missed last time.