Scaling fix for temperatures higher than model grid 

Grids of models run from Tmin to Tmax. Sometimes we might be in a situation where the disk or star will be hotter or cooler than the extremes of the grid.

What should happen: For a given annulus of temperature T is higher than the maximum Tmax in the grid, then go through each frequency bin where the fluxes are stored for that annulus and scale the fluxes up by a factor equal to the ratio of the BB functions at T and Tmax, i.e.:

```
scaling factor = B_nu ( T ) / B_nu (Tmax) = (exp(hnu / kTmax) - 1) / (exp(hnu / kT) - 1)
```

This was implemented for temperatures lower than Tmin but not for higher temperatures.
This pull request is a fix to this.

What about when log_g is out of range? -- there's not really a flux scaling factor there we can use.