More icon tweaks
Remove flicker when resizing textareas

The `EditTextWidget.prototype.fixHeight()` function was defering its
work with `nextTick()`, which led to flickering on all browsers when
typing triggers a resize.
Allow includeWikis to be read-only

Hopefully this will help resolve issues that @xcazin and @pmario have
been having with using the client-server configuration to prepare
translations of the TW5 docs.