Native emoji support warning

[muan]

Given #130, I'm considering adding a warning/announcement on the site to tell people that we're moving over to using native emoji, and for those who are using OS or browsers that don't support native emoji should do something about it or the site would be.. not as useful.

Current usage breakdown:

• iOS 47.39% ⭕
• Windows 18.80% ❌
• Android 18.00% ⭕
• Macintosh 12.95% ⭕
• Linux 1.59% ❓
• Chrome OS 0.68% ⭕

In Windows we then have 62.78% using Windows 7(no native color emoji), and 31.14% using Windows 8+(yes native color emoji).