feat(content): support complete local resource references (#388)

assets/svg/loading.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" style="margin:auto;background:0 0" width="60" height="60" viewBox="0 0 100 100" preserveAspectRatio="xMidYMid" display="block">
+    <circle cx="50" cy="50" r="20" stroke-width="4" stroke="#a5a5a5" stroke-dasharray="31.416 31.416" fill="none" stroke-linecap="round" transform="rotate(67.21 50 50)">
+        <animateTransform attributeName="transform" type="rotate" repeatCount="indefinite" dur="1s" keyTimes="0;1" values="0 50 50;360 50 50"/>
+    </circle>
+</svg>

assets/svg/loading/normal.svg

@@ -1,32 +0,0 @@
-<!-- By Sam Herbert (@sherb), for everyone. More @ http://goo.gl/7AJzbL -->
-<svg width="319" height="319" viewBox="-281 -281 600 600" xmlns="http://www.w3.org/2000/svg">
-    <defs>
-        <linearGradient x1="8.042%" y1="0%" x2="65.682%" y2="23.865%" id="a">
-            <stop stop-color="#a5a5a5" stop-opacity="0" offset="0%"/>
-            <stop stop-color="#a5a5a5" stop-opacity=".631" offset="63.146%"/>
-            <stop stop-color="#a5a5a5" offset="100%"/>
-        </linearGradient>
-    </defs>
-    <g fill="none" fill-rule="evenodd">
-        <g transform="translate(1 1)">
-            <path d="M36 18c0-9.94-8.06-18-18-18" id="Oval-2" stroke="url(#a)" stroke-width="2">
-                <animateTransform
-                    attributeName="transform"
-                    type="rotate"
-                    from="0 18 18"
-                    to="360 18 18"
-                    dur="0.9s"
-                    repeatCount="indefinite" />
-            </path>
-            <circle fill="#a5a5a5" cx="36" cy="18" r="1">
-                <animateTransform
-                    attributeName="transform"
-                    type="rotate"
-                    from="0 18 18"
-                    to="360 18 18"
-                    dur="0.9s"
-                    repeatCount="indefinite" />
-            </circle>
-        </g>
-    </g>
-</svg>

assets/svg/loading/small.svg

@@ -1,32 +0,0 @@
-<!-- By Sam Herbert (@sherb), for everyone. More @ http://goo.gl/7AJzbL -->
-<svg width="69" height="69" viewBox="-31 -31 100 100" xmlns="http://www.w3.org/2000/svg">
-    <defs>
-        <linearGradient x1="8.042%" y1="0%" x2="65.682%" y2="23.865%" id="a">
-            <stop stop-color="#a5a5a5" stop-opacity="0" offset="0%"/>
-            <stop stop-color="#a5a5a5" stop-opacity=".631" offset="63.146%"/>
-            <stop stop-color="#a5a5a5" offset="100%"/>
-        </linearGradient>
-    </defs>
-    <g fill="none" fill-rule="evenodd">
-        <g transform="translate(1 1)">
-            <path d="M36 18c0-9.94-8.06-18-18-18" id="Oval-2" stroke="url(#a)" stroke-width="2">
-                <animateTransform
-                    attributeName="transform"
-                    type="rotate"
-                    from="0 18 18"
-                    to="360 18 18"
-                    dur="0.9s"
-                    repeatCount="indefinite" />
-            </path>
-            <circle fill="#a5a5a5" cx="36" cy="18" r="1">
-                <animateTransform
-                    attributeName="transform"
-                    type="rotate"
-                    from="0 18 18"
-                    to="360 18 18"
-                    dur="0.9s"
-                    repeatCount="indefinite" />
-            </circle>
-        </g>
-    </g>
-</svg>