Add member company logos to home page

Author: jnewbery

_data/sponsors.yml

@@ -22,7 +22,27 @@ sponsors:
       "John and the Optech team have really taken the initiative to help build a higher level of communication and collaboration between industry and the open source development community.  We're just at the beginning of realizing the potential of Bitcoin and related technology, and I'm excited to see how much we can all accomplish working together."
 
 members:
+  -
+    name: BitGo
+    twitter: BitGo
+    logo: bitgo.png
+  -
+    name: Coinbase
+    twitter: Coinbase
+    logo: coinbase.png
   -
     name: Ledger
     twitter: LedgerHQ
-    avatar: https://pbs.twimg.com/profile_images/915545754084741120/N44_mYZ7_400x400.jpg
+    logo: ledger.png
+  -
+    name: Purse
+    twitter: PurseIO
+    logo: purse.png
+  -
+    name: Square
+    twitter: Square
+    logo: square2.jpeg
+  -
+    name: Xapo
+    twitter: xapo
+    logo: xapo.png

_includes/members.html

@@ -0,0 +1,21 @@
+{% assign members = site.data.sponsors.members %}
+
+<div id="members">
+
+	<h2>Member Companies</h2>
+
+	<p>Bitcoin Optech is supported by our member companies.</p>
+
+	<ul class="members n-column-list">
+	{% for member in members %}
+	{% assign logo=member.logo %}
+	{% unless member.logo contains 'https://' %}{% capture logo %}/img/members/{{member.logo}}{% endcapture %}{% endunless %}
+	<li>
+		<div style="max-height:150px;min-height:150px;display:flex;align-items:center">
+		<a href="https://twitter.com/{{ member.twitter }}"><img src="{{ logo }}" width="150" alt="{{ member.name }}" title="{{ member.name }}"></a>
+		</div>
+	    {% if member.quote %}<p class="member-quote">{{ member.quote }} </p>{% endif %}
+	</li>
+	{% endfor %}
+	</ul>
+</div>