add breadcrumbs component

res/css/_components.scss

@@ -126,6 +126,7 @@
 @import "./views/rooms/_PinnedEventsPanel.scss";
 @import "./views/rooms/_PresenceLabel.scss";
 @import "./views/rooms/_ReplyPreview.scss";
+@import "./views/rooms/_RoomBreadcrumbs.scss";
 @import "./views/rooms/_RoomDropTarget.scss";
 @import "./views/rooms/_RoomHeader.scss";
 @import "./views/rooms/_RoomList.scss";

res/css/views/rooms/_RoomBreadcrumbs.scss

@@ -0,0 +1,47 @@
+/*
+Copyright 2015, 2016 OpenMarket Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+.mx_RoomBreadcrumbs {
+    overflow-x: auto;
+    position: relative;
+    height: 32px;
+    margin: 8px;
+    margin-bottom: 0;
+
+    > div {
+        display: flex;
+        flex-direction: row;
+        position: absolute;
+        right: 0;
+        top: 0;
+        height: 32px;
+
+        > * {
+            margin-right: 4px;
+        }
+    }
+
+    &::after {
+        content: "";
+        position: absolute;
+        width: 15px;
+        top: 0;
+        left: 0;
+        height: 100%;
+        background: linear-gradient(to left, rgba(242,245,248,0), rgba(242,245,248,1));
+    }
+}
+