provided test fails due to too few data lines

The test described in the readme:

`./run_bmisnow_model ../../Snow_BMI_Fortran/data/snow_model_test.cfg`

fails with:

```
9.0   -1.39C    4.06mm    4.24cm 200.1kg per m3
At line 44 of file ./Snow_BMI_Fortran/snow/functions.f (unit = 201, file = './test_tair.csv')
Fortran runtime error: End of file
```

Fixed by setting "Total Time Steps:" to 10 in `snow_model_test.cfg`