Add Wagtail Space US 2019 presentations (#124)

The links, talk titles, people names are from the official YouTube playlist. The slides links are from the Slack channel :)

README.md

@@ -273,6 +273,17 @@ Awesome Wagtail [![Awesome](https://cdn.rawgit.com/sindresorhus/awesome/d7305f38
 - [My First Wagtail Contribution – More formats in RichText Editor – Wagtail Space 2019](https://youtu.be/CSwpj-jyjP4?t=4126) by Arifin Ibne Matin.
 - [Fly, Wagtail, fly! – Wagtail Space 2019](https://youtu.be/CSwpj-jyjP4?t=4404) by Daniele Procida.
 - [Wagtail & GraphQL – Wagtail Space 2019](https://youtu.be/YydSbL8gMS4?t=24) by Arthur Bayr.
+- [Writing (code) for authors – Wagtail Space US 2019](https://www.youtube.com/watch?v=Ihsrki0d1G8&list=PLEyaio0l1qoEIUFM9bnRKoN6VKEUOdxAn&index=1) by Brian Smith & Eric Sherman. [Slides](https://docs.google.com/presentation/d/1z61u0uKwJxmYS4Zawbu4Zgg-kCtInd1VgsEg-rnwzBE/edit).
+- [Saving Lives With Wagtail: Recovery Meetings Across the World – Wagtail Space US 2019](https://www.youtube.com/watch?v=QlLWvNT5Wrk&list=PLEyaio0l1qoEIUFM9bnRKoN6VKEUOdxAn&index=2) by Timothy Allen.
+- [Why we chose Wagtail for CodeRed CMS – Wagtail Space US 2019](https://www.youtube.com/watch?v=1JUOAAmLQFA&list=PLEyaio0l1qoEIUFM9bnRKoN6VKEUOdxAn&index=3) by Vince Salvino.
+- [Building a Wagtail-based site and authoring environment with accessibility in mind – Wagtail Space US 2019](https://www.youtube.com/watch?v=CxjlAI6R7iY&list=PLEyaio0l1qoEIUFM9bnRKoN6VKEUOdxAn&index=4) by Zarina Mustapha.
+- [Making Wagtail Accessible – Wagtail Space US 2019](https://www.youtube.com/watch?v=tdB1I_gSCeY&list=PLEyaio0l1qoEIUFM9bnRKoN6VKEUOdxAn&index=5) by Thibaud Colas. [Slides](https://docs.google.com/presentation/d/15y8XIe7SL-RYEO9tEE8n9chx80_X4j4PbczGGM-cEGE/edit).
+- [Everyone can fly a flag – Wagtail Space US 2019](https://www.youtube.com/watch?v=ZqwmgsqMTEs&list=PLEyaio0l1qoEIUFM9bnRKoN6VKEUOdxAn&index=6) by Will Barton. [Slides](https://docs.google.com/presentation/d/1-A1doke2ylcqG72oIP-MLiX8SKXKkKNxQeKxddYUGBw/edit).
+- [Architecting for a multi-domain site – Wagtail Space US 2019](https://www.youtube.com/watch?v=xMbJmHF7kCw&list=PLEyaio0l1qoEIUFM9bnRKoN6VKEUOdxAn&index=7) by Ben Beecher. [Slides](https://slides.com/benbeecher/mds/).
+- [Contributions can be more than code – Wagtail Space US 2019](https://www.youtube.com/watch?v=tK-3kEBbblg&list=PLEyaio0l1qoEIUFM9bnRKoN6VKEUOdxAn&index=8) by Kalob Taulien.
+- [Thoughtful Code Review – Wagtail Space US 2019](https://www.youtube.com/watch?v=RY0K1BEV-_U&list=PLEyaio0l1qoEIUFM9bnRKoN6VKEUOdxAn&index=9) by Naomi Morduch Toubman. [Slides](https://docs.google.com/presentation/d/1b_Hda8381G6mMc7uzYDc2EYjocfwSi2TYiRMI7d4e3I/).
+- [Solving your problems by spelunking the Wagtail code – Wagtail Space US 2019](https://www.youtube.com/watch?v=BMoOhjgirFM&list=PLEyaio0l1qoEIUFM9bnRKoN6VKEUOdxAn&index=10) by Harris Lapiroff. [Slides](https://harrislapiroff.github.io/wagtail-space-us-2019/)
+- [The State of Wagtail: 2019 – Wagtail Space US 2019](https://www.youtube.com/watch?v=s29vaGnFcq8&list=PLEyaio0l1qoEIUFM9bnRKoN6VKEUOdxAn&index=11) by Tom Dyson.
 
 ### Podcasts