Fix Enter key and maintain activeElement after closing select

After tabbing to a selectr element, pressing enter wouldn't activate the
selected state to display the selectr container.

After dismissing the dialog (e.g. via pressing enter), the tab focus was
lost thus starting you back over at the top of the document (making
using keyboard only navigation painful).

src/selectr.js

@@ -1134,19 +1134,22 @@
         }
 
         // Open the dropdown with Enter key if focused
-        if (this.config.nativeDropdown) {
-            this.container.addEventListener("keydown", function(e) {
-                if (e.key === "Enter" && that.selected === document.activeElement) {
-                    // Show the native
+        this.container.addEventListener("keydown", function(e) {
+            if ((e.key === "Enter" || e.key === "ArrowUp" || e.key === "ArrowDown") &&
+              that.selected === document.activeElement) {
+                // Show the native
+                setTimeout(function() {
                     that.toggle();
+                }, 200);
 
+                if (that.config.nativeDropdown) {
                     // Focus on the native multiselect
                     setTimeout(function() {
                         that.el.focus();
                     }, 200);
                 }
-            });
-        }
+            }
+        });
 
         // Non-native dropdown
         this.selected.addEventListener("click", function(e) {
@@ -2043,6 +2046,7 @@
 
         util.truncate(this.tree);
         clearSearch.call(this);
+        this.selected.focus();
     };