v2.10.2: more clarity in UI, more consistent behaviour of saving, permalinks, class syntax, and more

Changes summary:

• Behavior improvements:
  • Supports async saving of RSS;
  • Wiki syntax now supports classes with dashes ({{class-name{...}}}).
• UI updates (see the visual summary):
  • Tags blocks now have non-transparent background (and don't interfere with headers/tabs);
  • Tables now also have non-transparent background, reducing interference when they overflow the container;
  • Lists in sidebar and messages got more space between items (and group multiline ones visually);
  • Editor inputs and textareas got better paddings.
• Fixes:
  • Permalink's getUrl should work correctly even if location.href has no hash;
  • When saving failed, the error message was not displayed;
  • (hotfix, backported to 2.10.1) build_external_core.js should point to jQuery in node_modules.
• Hackability:
  • Since saveRss now supports async saving, it is compatible with new saving methods.
• Infrastructure:
  • Introduced bump-version script ({{{npm run bump-version}}}) for easier releasing.
• Lingo updates (for translations)
• Docs updates include clarifying/updating InstallingPlugins, [[Customisation]], [[Importing Tiddlers]], [[Plugins]], [[TiddlyWiki Browser Compatibility]], [[Mathematics]], SpecialTiddlers, [[Editing]], various links, and mentioning ContinuousSavingPlugin.

See the full changelog in #312