fix emoji rendering (force font emoji for everything)

use hybrid emoji (different fonts for better UX)
add missing Twemoji.Mozilla license

render/fonts/Mozilla/LICENSE.md

@@ -0,0 +1,50 @@
+## License for the Code
+
+Copyright 2016-2018, Mozilla Foundation
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+
+
+## License for the Visual Design
+
+The Emoji art in the twe-svg.zip archive comes from [Twemoji](https://twitter.github.io/twemoji),
+and is used and redistributed under the CC-BY-4.0 [license terms](https://github.com/twitter/twemoji#license)
+offered by the Twemoji project.
+
+### Creative Commons Attribution 4.0 International (CC BY 4.0)
+https://creativecommons.org/licenses/by/4.0/legalcode
+or for the human readable summary: https://creativecommons.org/licenses/by/4.0/
+
+
+#### You are free to:
+**Share** — copy and redistribute the material in any medium or format
+
+**Adapt** — remix, transform, and build upon the material for any purpose, even commercially.
+
+The licensor cannot revoke these freedoms as long as you follow the license terms.
+
+
+#### Under the following terms:    
+**Attribution** — You must give appropriate credit, provide a link to the license,
+and indicate if changes were made.
+You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
+
+**No additional restrictions** — You may not apply legal terms or **technological measures**
+that legally restrict others from doing anything the license permits.
+
+#### Notices:
+You do not have to comply with the license for elements of the material in the public domain
+or where your use is permitted by an applicable exception or limitation. No warranties are given.
+The license may not give you all of the permissions necessary for your intended use.
+For example, other rights such as publicity, privacy, or moral rights may limit how you use the material.