templates: mark index.html as a template (fixes #167)

After a66f11a48e (part of #137), we only treat UI files ending in
'.tmpl' as Jinja2 templates. This meant that the index.html file was
not expanded when deploying. The authentication code thus looked like
this:

  client = new ZeroCloudClient();
      var opts = {{ auth_opts }};

which isn't syntactically valid JavaScript code.

This was apparently not discovered until now since I've mostly been
deploying a test app which provides its own UI.
templates/index: load correct system.map file

After d0325d7ac043 (part of #163), the job description template file
has the fixed name boot/system.map. It was <zapp-name>.json before.

The auto-generated JavaScript code still used the old variable name
and one could thus not execute anything with the web interface.
zpm: update docstrings and comments to match d0325d7ac0

They still referred to the <zapp-name>.json file which became
boot/system.map in d0325d7ac0. This was added with #163.
Merge pull request #169 from mgeisler/fixes

Fixes for the web interface