Use utf-8 for data: URIs when downloading
Avoid using Chrome's @@bidi_* type i18n messages

... for the sake of portability.

When including vapi-common.js in an HTML file, then the body element there
will have a "dir" attribute filled with the current locale's direction
(ltr or rtl).

The following languages are considered right-to-left: ar, he, fa, ps, ur.
Everything else is left-to-right.

After the "dir" attribute is set, we can decide in CSS which elements
should have different styling for rtl languages (e.g., body[dir=rtl] #id).