More tweaks to the 'updateValue' method

In this release, I took another stab at the implementation of the updateValue method to make it ubiquitously applicable to the vast majority of scenarios. I recently became aware that the original implementation was incompatible with common front-end libraries like Vue, causing input that was supposed to replace existing content to be appended instead.

The new implementation uses JavaScript to replace the existing content if the browser supports it. Otherwise, updateValue employs basic key sequences to overwrite the field content with the new value.

To facilitate testing of this new behavior, I added an htmlunit.nojs personality that provides HtmlUnit sessions with JavaScript support turned off.