Sre v2.1.1

[zorkow]

Upgrades to the latest version of SRE. Adapts the a11y menu as discussed:

• removes generation options
• replaces selection of walkers by a binary choice to switch walker on or off. Both generation and walker options can still be altered in the default configurations for the explorer and a therefore reachable.

NOTE: PR does not update the walker selection in the labs, though.

[zorkow]

Following f2f: The correct configuration parameters already exists. So we are now using the parameters in hub.config for walker and generation instead of the menu entries.

[dpvc]

OK, I was worried that the setDefaults() function, by populating the menu settings with the default values, would cause those values to be saved in the menu cookie if some other menu option was changed by the user. It appears that isn't the case, so I think you are OK at this point.

In hindsight, I think that saving the defaults in the menu settings (SETTINGS[]) is probably the wrong approach, and that getOption() should check the menu settings, the configuration, and the defaults, in that order, and return the first one that is found, and then always use getOption() rather than using SETTINGS[] directly (as it is in a few places). But it is probably not worth it at this point, as all of this will be changing in v3. The menu (if there is one) is probably going to be an extension, not part of the core, and the API for hooking into it will have to be more robust.

In any case, you can merge this.