RDF.rb /sparql public domain dedications

# Copyright waiver for <https://github.com/ruby-rdf/sparql>

I dedicate any and all copyright interest in this software to the
public domain. I make this dedication for the benefit of the public at
large and to the detriment of my heirs and successors. I intend this
dedication to be an overt act of relinquishment in perpetuity of all
present and future rights to this software under copyright law.

To the best of my knowledge and belief, my contributions are either
originally authored by me or are derived from prior works which I have
verified are also in the public domain and are not subject to claims
of copyright by other parties.

To the best of my knowledge and belief, no individual, business,
organization, government, or other entity has any copyright interest
in my contributions, and I affirm that I will not make contributions
that are otherwise encumbered.