Add a demo/sourcing.vars file to be used by the associated demo
script.
Modified mo argument parsing so that --help and --source=file do not need
to be the first arguments for mo. And can in fact appear after or in the
middle of filenames.
Bug: Did not properly detect the length of an array in mustache-test
because I neglected to use `[@]` after the array name. This closes
issue #6.
Feature: Made {{ARRAY_NAME}} implode array values with commas.
Feature: Added an associative array demo script.