This commit permits language plugins to carry the field
“text-direction” with the value “rtl” to trigger right-to-left layout
of the entire page. We also adjust the sidebar layout to work in RTL
mode.
There are still a number of problems to be addressed:
* Brackets and other punctuation incorrectly placed within en-GB UI text
* System tiddler titles are rendered semi-back-to-front (eg
`languages/ca-ES/:$`)
Starting to address #1845 and the discussion in #2523.
Now we’re just using the word “lingo” for the macro defined in
PageTemplate (where the abbreviation is useful), and using the full
word “language” everywhere else.
It’s possible that we should be using “locale” instead of “language”,
what do you think?
