CSS selection style to dark gray on black

Use spaces instead of tabs

Update to MongoDB 5 conventions

Modify for changed JSON result of MongoDB 3 insert

Remove _id and commit_id from the reveals, closes #48

Mode transition fixes for commit/protect=>show in single page demo

Always throw Error subclasses instead of strings, closes #38

Move blackhighlighter.org-demo-specific show and verify URLs into that demo

Move ClientError into shared widget/server exports

Custom error type for Timestamp skew, MultipleError common type

Add commit ID test for a fixed commit

Remove redundant copy of native JS escapeHtml code

Transition comments to links to blog articles, move HTML gen into shared lib

README.md reflecting being an NPM package, move exposition to homepage

Multiple commit, reveal, or query in single network request, closes #50