first attempt with MPFIT
This is a practice commit to learn about using git.  The only file
modifications were silly comments.
Adding a git ignore file to avoid saving emacs temporary files.
Dump the temporary README file (for testing git).
Update the version of the program, 'simple_fit.pro' so David can see
what it looks like.

Added plots showing various ways of running the code:
      - first attempt, including noise & intrinsic variance, fitting
            for both: *_Run1.png
      - with only noise (no intrinsic variance): *_JustNoise.png
      - with only noise, but more of it: *_MoreNoise.png
      - with noise + intrinsic variance, fitting only for the mean:
      	     *_FitMean.png
      - same as above, but inflating the error in the fit:
      	     *_FitMean_InflateErr.png
      - fitting for both mean and intrinsic variance (as in Run1), but
            inflating the error in the fit: *_FitAll_InflateErr.png
Merge branch 'master' of https://github.com/genevievegraves/SpecStack

I am just figuring this out: files on my local disk are the main ones,
the stuff online are just dummy files (README, etc.) that I set up
while learning to use my account.  They are unnecessary, but won't do
any harm to merge.