WebXDC improvements * WebXDC "store" to choose a widget to add * WebXDC UX improvements, especially for widgets that use touch events * WebXDC experimental "realtime" API support * Improve display of images shared from WebXDC * Fix top spacing in chat bubbles * Fix colour of "send private message" indicator * Improve thread identicon contrast * Fixes for rich reply markup processing * Fix for large font on a retracted message that was a reply * Improvements to showing what a MUC "actually" sent