Pattern matching problems

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Species: R(l,l!1,Y~0).L(r!1,r!2).R(l!2,l!3,Y~1).L(r!3,r!4).R(l!4,l,Y~1)
Observable: Molecules Five L(r!1).R(l!1).R(Y~1)

In BNG, the observable evaluates to 5 when applied to the species. In NFsim, it 
evaluates to 4. I suspect that the root of the problem is that the last R 
molecule in the pattern isn't bound to anything. When starting from the 
left-most L molecule in the species, I suspect that NFsim isn't walking past 
the R(l!2,l!3,Y~1) molecule to find the match at R(l!4,l,Y~1). 

Original issue reported on code.google.com by [email protected] on 12 Mar 2015 at 8:39