Deprecate and remove the dictionary file?

[martindholmes]

@joeytakeda suggests that we're now only using the dictionary file for the processing report; if so, we can remove complexity and overhead by getting rid of it in 2.0. See also #195.

[martindholmes]

As far as I can see, the only additional complexity involved is the fact that the report process uses the file, and in the past I've found it very useful for finding typos and spelling errors. How about this, instead:

• dictionary file is optional in config

• if it's not supplied, that part of the report process doesn't run, but if it is, the process does run.

  So by supplying a dictionary file, you're telling the build process that you want a detailed report.

I do think we should relocate those files from the xsl folder, though; maybe to a lexicon folder, or something like that.

[martindholmes]

See also #186.