Update dictionaries URL

Fix dictionary generation command

Some WiktionarySplitter fixes

Update URLs. Wiktionary dumps require HTTPS now.

Switch to --release option instead of source and target

Modernize codebase

Simplify using text blocks.

Remove pointless class

Remove unused file

Trivial automated codfe simplifications

Adjust for moved file

Fix compilation

Improve error message wording.

Sanity-check "Dictionary" checkout.

Add documentation for adding a language.