Move tabs stylesheet into package directory

src/packages/tabs/stylesheets/tabs.less

@@ -0,0 +1,110 @@
+.tabs {
+  font: caption;
+  display: -webkit-flex;
+  -webkit-box-align: center;
+}
+
+.tab {
+  -webkit-user-select: none;
+  -webkit-user-drag: element;
+  cursor: default;
+  -webkit-flex: 1;
+  width: 175px;
+  max-width: 175px;
+  min-width: 40px;
+  box-sizing: border-box;
+  text-shadow: -1px -1px 0 #000;
+  font-size: 11px;
+  padding: 5px 10px;
+  position: relative;
+}
+
+.tab.active {
+  -webkit-flex: 2;
+}
+
+.tab .title {
+  display: block;
+  overflow: hidden;
+  white-space: nowrap;
+  text-overflow: ellipsis;
+  padding: 3px 10px 3px 0;
+}
+
+.tab .close-icon {
+  font-family: 'Octicons Regular';
+  font-size: 12px;
+  width: 12px;
+  height: 12px;
+  cursor: pointer;
+  position: absolute;
+  color: rgba(255, 255, 255, 0.5);
+  right: 8px;
+  top: 5px;
+  -webkit-font-smoothing: antialiased;
+}
+
+.tab .close-icon:before {
+  content: "\f081";
+}
+
+.tab .close-icon:hover {
+  color: #fff;
+}
+
+.tab.modified .close-icon {
+  top: 11px;
+  width: 5px;
+  height: 5px;
+  right: 9px;
+  border: 2px solid #66a6ff;
+  border-radius: 12px;
+}
+
+.tab.modified .close-icon:before {
+  content: "";
+}
+
+.tab.modified:hover .close-icon {
+  border: none;
+  width: 12px;
+  height: 12px;
+  right: 8px;
+  top: 5px;
+}
+
+.tab.modified:hover .close-icon:before {
+  content: "\f081";
+  color: #66a6ff;
+}
+
+/* Drag and Drop */
+.tab.is-dragging {
+
+}
+
+.tab.is-drop-target:after {
+  position: absolute;
+  top: 0;
+  right: -2px;
+  content: "";
+  z-index: 999;
+  display: inline-block;
+  width: 2px;
+  height: 30px;
+  display: inline-block;
+  background: #0098ff;
+}
+
+.tab.is-drop-target:before {
+  content: "";
+  position: absolute;
+  width: 4px;
+  height: 4px;
+  background: #0098ff;
+  right: -4px;
+  top: 30px;
+  border-radius: 4px;
+  z-index: 9999;
+  border: 1px solid transparent;
+}