Replace "1" with ivis and "2" with inir wherever appropriate throughout the code

**Incomplete list of examples**

**DryDepVelocity**
`solar_flux = forc_solad(g,1)`

**VocEmissionMod**
`par_sun = (forc_solad(g,1) + fsun(p) * forc_solai(g,1)) * 4.6_r8`

**SurfaceRadiationMod**
```
fsds_sno_vd(p) = forc_solad(g,1)
fsds_sno_nd(p) = forc_solad(g,2)
```