Release 1.91

* Version numbers now track schema.org versioning.
* Improve humanized display of dates and times when no timezone is present.
* Show a warning for the use of superseded terms.
* Don't complain about undefined terms from non-included vocabularies.
* Improve tabluar-view nesting for BNodes.
* Display @id for each element, except items with a BNode only used as a value or otherwise unreferenced at the top-level.
Update jQuery version and remove some cruft.
Progress on using Angularjs.
More style updates.
Use unicode rating stars, as Ajax doesn't run javascript, and the output is sanatized.
Remove cache directory from repo.
URL and content from app.
Start up parsing from URL parameters, if present.
As displayed markup is sanitized, remove form elements, ids and style info.
Update URL with query parameters as needed.
Add parser statistics.
Validate SSL => Verify SSL.
File upload.
Update specs.
Update travis Ruby version.
Update schema.org examples for 2.0/venkman.
Regenerate schema-warnings.
Added API and contribution information to About page.
Version 2.0.
Release 2.0.

* Linter UI now implemented as an HTML Web Application using AngularJS.
* Linting services now operated using JSON requests, as described in the About section.
* Requests are cached using HTTP caching semantics and Rack::Cache.
* Verfiy SSL is now an option, rather than always being applied.
* Updated schema.org examples for the 1.92 \"Venkman\" release.