Tighten up CSS

- Remove extra padding at top of Android bubbles, via sibling selector
- Don't include .attachments, .quote-wrapper, .content in bubble unless
  we actually need them. This allows for sibling selectors.
- This is a different technique for adding the ReactWrapperView for
  quotes - it is now appended to the DOM instead of attaching to
  something already in the DOM. This allows us to use .remove(), so it's
  a bit cleaner.
- Users of ReactWrapperView can now specify tagName and className

js/views/react_wrapper_view.js

@@ -17,6 +17,8 @@
       const { Component, props, onClose } = options;
       this.render();
 
+      this.tagName = options.tagName;
+      this.className = options.className;
       this.Component = Component;
       this.onClose = onClose;