Updated mediawiki/extensions
Project: mediawiki/extensions/Math  f971af901fb7dff8fbd94dc1129acb232baab9e0

Remove even more unused variables

* $inputhash is also never used.
* Additional comments.
* allow creation of math renderer without $tex code

Change-Id: I64c181408e8acd16aee7a53a81a176b62a6726b5