* Add `main` and `article` roles to stories and story.
* Support `role` and \aria-checked` in buttons, and integrate with sidebar tabs.
* Add `region` role to sidebar, and set caption as `aria-label`.
* Add accessibility roles and labels to static templates.
* Update test fixtures with new ARIA tab attributes.
Global variables access within attributes will automatically trigger a refresh if the attribute text changes, but that wasn't happening for transclusions.
The objective is to add a $depth attribute so that it is possible to reach up to retrieve the parameters of ancestor transclusions. However, doing so requires changing the encoding of parameter names so that it is not possible for a user parameter to clash with an attribute like $depth. So now we have to double up dollars on any attribute names seen by the parameters widget, just like with the transclude widget itself.
Can invoke any functions, not just those start with a period. And can pass zero parameters (in contrast when invoked as a custom filter operator there's no way to omit the first parameter).
So far it appears to be totally backwards compatible... In practice, I think maybe this and the conversion of the other macros should go into a separate subsequent PR.
The basic idea is that if we don't find a variable `foo` then we fallback to retrieving the value from the tiddler `$:/global/foo`, if it exists.
This allows us to replace the usual importvariables-based mechanism for global definitions, avoiding cluttering up the variable namespace with every macro.
In order to permit subprocedures to be overridden, we also introduce a mechanism for conditional definitions: preceding the word definition|procedure|function|widget with a + causes the definition only to occur if the specified variable doesn't already exist. In the next commit we'll apply this mechanism to the tabs macro
There are two big changes here:
Replace the previous "ts-wrapper" mechanism, which we had been using to redefine custom widgets inside their definitions to prevent recursive calls. Now we've got the genesis widget we can instead control recursion through a new "$remappable" attribute that allows the custom widget mechanism to be skipped.
We also extend the slot widget to allow a depth to be specified; it then reaches up by the indicated number of transclusion widgets to find the one from which it should retrieve the slot value.
