[Pdweb] removing unused 'Hardware' and 'Language Bindings' from downloads

[Hans-Christoph Steiner]

It looks like recently someone added  'Hardware' and 'Language Bindings'
categories to the downloads page.  My guess is that IOhannes did this.  I
think this is a bad idea because it makes the download page too cluttered to
be useable, and people can already search using keywords to find specific things.

Having too many categories will make it more confusing to use the downloads
page, both for newbies and for people who want to place their code up there.

.hc