get rid of hardcoded font

src/skins/vector/img/button-text-formatting.svg

@@ -1,18 +1,21 @@
-<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<svg width="24px" height="18px" viewBox="0 0 24 18" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
-    <!-- Generator: sketchtool 39 (31667) - http://www.bohemiancoding.com/sketch -->
-    <title>F69CBF5F-0BEC-47E8-B1DF-125D6376C0C9</title>
-    <desc>Created with sketchtool.</desc>
-    <defs></defs>
-    <g id="Screens-revised" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd">
-        <g id="02_x-Chat-text-input-" transform="translate(-829.000000, -729.000000)">
-            <g id="button_text_formatting" transform="translate(829.000000, 729.000000)">
-                <rect id="Rectangle-111" fill="#F6F6F6" x="0" y="0" width="24" height="18" rx="9"></rect>
-                <text id="Aa" font-family="OpenSans-Bold, Open Sans" font-size="12" font-weight="bold" letter-spacing="-1.20000005" fill="#4A4A4A">
-                    <tspan x="5" y="13">A</tspan>
-                    <tspan x="12.0792968" y="13" font-family="OpenSans-Italic, Open Sans" font-style="italic" font-weight="normal">a</tspan>
-                </text>
-            </g>
-        </g>
-    </g>
-</svg>
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Generator: Adobe Illustrator 21.0.0, SVG Export Plug-In . SVG Version: 6.00 Build 0)  -->
+<svg version="1.1" id="Layer_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
+	 viewBox="0 0 24 18" style="enable-background:new 0 0 24 18;" xml:space="preserve">
+<style type="text/css">
+	.st0{fill:#F6F6F6;}
+	.st1{enable-background:new    ;}
+	.st2{fill:#4A4A4A;}
+</style>
+<path id="Rectangle-111" class="st0" d="M9,0h6c5,0,9,4,9,9l0,0c0,5-4,9-9,9H9c-5,0-9-4-9-9l0,0C0,4,4,0,9,0z"/>
+<g class="st1">
+	<path class="st2" d="M11.3,13l-0.6-2H7.6L7,13H5l3-8.6h2.2l3,8.6H11.3z M10.3,9.4c-0.6-1.8-0.9-2.9-1-3.1S9.2,5.9,9.1,5.7
+		C9,6.2,8.6,7.5,8,9.4H10.3z"/>
+</g>
+<g class="st1">
+	<path class="st2" d="M15.8,6.5c0.4,0,0.7,0.1,1,0.3s0.5,0.5,0.7,0.8h0.1l0.4-1h0.7L17.3,13h-0.8l0.2-1.2h0
+		c-0.7,0.9-1.4,1.3-2.2,1.3c-0.5,0-1-0.2-1.3-0.6s-0.5-0.9-0.5-1.6c0-0.8,0.1-1.6,0.4-2.3s0.7-1.2,1.1-1.6S15.2,6.5,15.8,6.5z
+		 M14.7,12.3c0.4,0,0.8-0.2,1.1-0.5s0.7-0.8,0.9-1.4s0.4-1.2,0.4-1.7c0-0.4-0.1-0.7-0.3-1s-0.5-0.4-0.9-0.4c-0.4,0-0.8,0.2-1.1,0.5
+		S14.2,8.6,14,9.2s-0.3,1.2-0.3,1.8c0,0.4,0.1,0.8,0.3,1S14.4,12.3,14.7,12.3z"/>
+</g>
+</svg>