How to add namelist variables

1. Edit Registry/registry.fire to add a line of with fist column rconfig. It should be clear from the lines already there how. Use NumTLev 1. Then you need to put the variable in namelist.input line only once. If you use MaxLevels, Otherwise you will need to guess how many levels there are and hit the correct one. (Ideally, the finest level where the fire model lives, should be the first, then it would not matter, but we are not so lucky, many models are configured so that the finest domain is the last. We really should have used 1 from the beginning always. Oh well.)