Add input_type back to context

[hdoupe]

@GoFroggyRun's comment in PR #760 led me to this solution. In particular, @GoFroggyRun said:

In particular, before this PR, some code in input_base.html reads:

  {% if input_type == "file" %}
  <script src="{% static 'js/filetb.js' %}"></script>
  {% else %}
  <script src="{% static 'js/taxbrain.js' %}"></script>
  {% endif %}

The if loop here, however, will always fall into the else clause, and thus causing #760.

In PR #641, I removed this from the context. Sometimes I do things that are both extremely frustrating and highly amusing. This happens to be one of them. Check out this comment:

[hdoupe]

PR #767 is ready for review. It's been pushed to the test server along with changes in #762

[GoFroggyRun]

@hdoupe +1

[hdoupe]

Thanks for the review @GoFroggyRun