`plot_sncm_fit()` only accepts "i_spp.out" as input.

[LijMeh]

Hello,

Firstly, thanks for taking the time to create this package, its been a huge timesaver!

Secondly, I noticed that the plot_sncm_fit() function will only accept the input if it is named i_spp.out. Looking at the function in modeling_tools.R the object i_spp.out is referenced starting on line 174, but the object itself isn't created prior to that.

[DanielSprockett]

Thank you for bringing this to my attention! I'm not able to address this issue this week, but I'll try to get to it as soon as possible. It should be an easy fix.