Add twitter button.

assets/icons/twitter.svg

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   viewBox="0 0 18 18"
+   style="enable-background:new 0 0 18 18"
+   xml:space="preserve"
+   version="1.1"
+   id="svg6"
+   sodipodi:docname="twitter.svg"
+   inkscape:version="0.92.3 (2405546, 2018-03-11)"><metadata
+     id="metadata12"><rdf:RDF><cc:Work
+         rdf:about=""><dc:format>image/svg+xml</dc:format><dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" /><dc:title></dc:title></cc:Work></rdf:RDF></metadata><defs
+     id="defs10" /><sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="1920"
+     inkscape:window-height="1137"
+     id="namedview8"
+     showgrid="false"
+     inkscape:zoom="9.2709556"
+     inkscape:cx="29.491041"
+     inkscape:cy="-26.815678"
+     inkscape:window-x="-8"
+     inkscape:window-y="-8"
+     inkscape:window-maximized="1"
+     inkscape:current-layer="svg6" /><path
+     id="path880"
+     d="M 9.0003652,0 C 4.0296052,0 0,4.030337 0,9.000365 0,13.971125 4.0296052,18 9.0003652,18 13.971126,18 18,13.971125 18,9.000365 18,4.030337 13.97076,0 9.0003652,0 Z m 4.5336258,7.185673 c 0.0048,0.09722 0.0066,0.19481 0.0066,0.293494 0,2.99744 -2.281433,6.453215 -6.4532158,6.453215 -1.280702,0 -2.473319,-0.375365 -3.476974,-1.01864 0.177632,0.02083 0.357822,0.03143 0.540936,0.03143 1.062865,0 2.040935,-0.362573 2.816886,-0.970761 -0.992325,-0.01864 -1.829679,-0.674707 -2.118421,-1.575657 0.138157,0.02705 0.280336,0.04057 0.426535,0.04057 0.206871,0 0.407163,-0.02705 0.597587,-0.07931 -1.038011,-0.208333 -1.81981,-1.125731 -1.81981,-2.223683 0,-0.0099 0,-0.01937 3.66e-4,-0.02924 0.305555,0.169956 0.655336,0.27193 1.027412,0.283991 -0.608918,-0.407529 -1.009137,-1.100877 -1.009137,-1.888158 0,-0.41557 0.111842,-0.805555 0.307017,-1.140351 1.118787,1.372076 2.790205,2.27522 4.675439,2.369518 -0.03874,-0.16557 -0.05885,-0.339181 -0.05885,-0.516813 0,-1.252193 1.0153508,-2.267909 2.2682748,-2.267909 0.652412,0 1.241593,0.275585 1.655336,0.716009 0.516813,-0.101243 1.002193,-0.290571 1.440424,-0.550439 -0.169956,0.529971 -0.52924,0.974415 -0.997807,1.254751 0.45943,-0.05482 0.896564,-0.1769 1.302997,-0.35709 -0.303363,0.455775 -0.688231,0.855263 -1.131579,1.175073 z"
+     inkscape:connector-curvature="0"
+     style="fill:#263238;fill-opacity:1;stroke-width:0.36549708" /></svg>

website/o3dv/css/icons.css

@@ -1,6 +1,6 @@
 @font-face {
     font-family: "O3DVIcons";
-    src: url("O3DVIcons/O3DVIcons.woff?24e3cf024c0a013e23e536baef079fe1") format("woff");
+    src: url("O3DVIcons/O3DVIcons.woff?7bda82bc77fb1b1ae8401407a3623f2c") format("woff");
 }
 
 i[class^="icon-"]:before, i[class*=" icon-"]:before {
@@ -113,15 +113,18 @@ i[class^="icon-"]:before, i[class*=" icon-"]:before {
 .icon-tree_view:before {
     content: "\f121";
 }
-.icon-up_y:before {
+.icon-twitter:before {
     content: "\f122";
 }
-.icon-up_z:before {
+.icon-up_y:before {
     content: "\f123";
 }
-.icon-visible:before {
+.icon-up_z:before {
     content: "\f124";
 }
-.icon-warning:before {
+.icon-visible:before {
     content: "\f125";
 }
+.icon-warning:before {
+    content: "\f126";
+}