HttpAuthPlugin gone?!

I cannot seem to find how to fix this. On Piwik 1, I had been using the HttpAuth plugin so that our single sign on system could authenticate people (as directed by the .htaccess file) and Piwik would just the REMOTE_USER as the username. When I upgraded to Piwik 2.0.3, I found that this was now gone, which means I cannot have people authenticate outside of Piwik to access Piwik. How do I fix this?

I saw posts about adding username and password to the URL for Basic Auth. That’s now that I’m talking about.

There seems to be a new version of the plugin posted at New Plugin: Provide HTTP_AUTH Authentication for Piwik - Release in Marketplace · Issue #514 · matomo-org/matomo · GitHub

That looks on the right track but downloading and putting that plugin in the folder and adding to config.ini.php still doesn’t work. Piwik 2.0.3 tells me it is incompatible. :-/