Allow users to setup a GEOSldas experiment from somebody else's build

[mathomp4]

Closes #699

This is my attempt at making ldas_setup.py usable by anyone. This (I think) should use a tempfile instead. Perhaps @biljanaorescanin can try it? Well I guess there are two tests:

• Builder of the clone can make an experiment
• Someone else can make an experiment using another's install dir

ETA: Note: my editor strips whitespace, so probably good to "hide whitespace" in the Files changed tab.

[weiyuan-jiang]

Thanks @mathomp4 . This is a great start. But I believe it is not enough. The fortran program will produce a temporary file "f2g.txt". I am wondering if fortran can accept it and write to it. I will try.

[mathomp4]

Thanks @mathomp4 . This is a great start. But I believe it is not enough. The fortran program will produce a temporary file "f2g.txt". I am wondering if fortran can accept it and write to it. I will try.

Ohh. I didn't know about f2g.txt. Can the commands that need that file accept an input/output file name? Then I suppose you could make another NamedTemporaryFile, and pass that filename into the the commands that need it. Then it would all be temp files.

[gmao-rreichle]

I was able to verify that I can setup and run an experiment using Weiyuan's build.
I also ran the nightly tests, which all passed except for the expected comparison "failure" for the new 6-h inst output in the LDAS_*GLOBAL/model tests.