add a gitignore file
adding Ruth's code from her testing repo
Merge branch 'add-ruths-code' into cal-prototype
rough draft of monthly thermal plot
Change so that json files are stored (and ignored by git) in a sub-directory.
Merge branch 'many-json-files' into cal-prototype

This is rudimentarily working. On the mac, I installed the
jsoncpp library with:
    $ brew tap cuber/homebrew-jsoncpp
    $ brew install jsoncpp

Then compile the jsoncpp_test.cpp with this line:
    $ g++ -ljson jsoncpp_test.cpp

Then in one terminal, run:
    $ ./a.out

Which will generate the json files...
In the second terminal run:
    $ python plot_monthly_thermal.py

Which will draw the graphs. Adjust the animation interval
in the plotter, and the usleep() call in the C++ to try
different behaviors.
A little cleanup of the ZMQ attempt.

For some reason this is not blocking any more, but I am
sure it will if I adjust the socket parameters.

Should refactor to follow the pattern used in the other plot
that uses many persistent json files. Seemed cleaner for the
plotting code.