Case file for windninja

[ksshannon]

Design and implement a case file.

• Case files will be optional.
• Case files will be immutable.
• Users can load an existing file but not save back to it, unless they overwrite the old.
• Output grids will be saved to the file.

[ksshannon]

After working on some other things (mostly wx), I really want this. It's a big change I think though, but simplify so much stuff. I changed my mind on a few things above, I think we should be allowed to append to a case file so it can hold multiple forecasts and outputs. Once a surface file is written, it can't be changed. Same with any outputs generated. One of the issues I forsee is reading directly from the case file, but I think we can figure that out. We typically don't do too much memory work outside of the solver, so maybe we are okay. I'm going to write up a schema and an interface, and we can go over it.

[jforthofer]

I think a case file would be good also for a lot of reasons.

[nwagenbrenner]

We should include some information about the WindNinja version here too. Chuck recently asked for this.