[feat]: In-memory implementation of c14n algorithm

[jeswr]

Might be useful to have a class similar to the Reasoner which implements the c14n algorithm over the N3.js index. A reference implementation of the algorithm operating at the RDF/JS layer can be found at https://github.com/iherman/rdfjs-c14n.

[TallTed]

For the benefit of future GitHub searches, and people who don't have all the abbreviations in their heads...

c14n == canonicalization