The example puzzle is the same as the one in the Sudoku solver test, except with
several more cells filled in. Using the original causes :eflame to time out
while creating the final report (see
proger/eflame#13).

Ensure rebar is installed (the original, not rebar3), and run the following:

    $ MIX_ENV=prod mix do clean, deps.get, deps.compile, compile
    $ MIX_ENV=prod iex -S mix run -e "Backtrex.Profiler.eflame; exit(:normal)"
    $ ./deps/eflame/stack_to_flame.sh < stacks.out > flame-prod.svg

Credit goes to http://learningelixir.joekain.com/profiling-elixir-2/ for getting
me started.

Runs fprof and eflame on all combinations of backends and frontends, each with
a list of input problems they can handle.

Ignore fprof's "Unknown functions" because they don't seem to be included in the
Erlang PLT. Add mix as an explicit dependency to resolve the warning about the
custom mix task.

Backtrex.Profiler calls the script, but it was never committed.