Test scripts robustness

[ianhinder]

store-ref-data.sh: Ensure run from testing directory and make more robust

• Add shopt -s nullglob to make sure that ../examples/*
  expands to nothing rather than to itself when there are no matches.
  Otherwise, running in the LIFE directory leads to rm -rf *!
• Add an explicit check that the script is run in the right directory, and
  give a helpful error message if it isn't.
• Quote variable expansions. This ensures that the script works if there
  are spaces or shell metacharacters in variables. It would also have
  stopped the "*" being interpreted as a wildcard.
• Remove variable expansions from printf format string. If the variables
  have printf format characters (e.g. %) in them, it would lead to unintended
  results.

Mostly, this is just defensive bash programming. Issues like these can
be found easily using shellcheck, either on the command line, or at
https://www.shellcheck.net. Integrating a shell checker in your editor
is also helpful (I use flycheck for emacs).

Or just use python :)

run-tests.sh: Add check for correct directory and make more robust

Now passes shellcheck.

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I have tested that storing the reference data and running the tests works after this change.