feature: double click to copy/generate

Double-click on a credential now copies
the code to the clipboard. If it is a touch or
HOTP credential a code is generated as well.

The generate code action also copies the code to
the clipboard.

Should resolve #146

qml/YubiKey.qml

@@ -269,6 +269,10 @@ Python {
         // after update, since the code now
         // might be available.
         selected = cred
+        // When a single credential is updated,
+        // it is manually triggered and therefore
+        // should be copied to the clipboard.
+        copy()
     }
 
     function addCredential(name, key, oathType, digits, algorithm, touch, cb) {

qml/main.qml

@@ -268,6 +268,8 @@ ApplicationWindow {
                                 anchors.fill: parent
                                 onClicked: handleMouseClick(mouse, index,
                                                             modelData)
+                                onDoubleClicked: handleCredentialDoubleClick(mouse, index,
+                                                                             modelData)
                                 acceptedButtons: Qt.RightButton | Qt.LeftButton
                             }
 
@@ -602,6 +604,21 @@ ApplicationWindow {
         }
     }
 
+    function handleCredentialDoubleClick(mouse, index, modelData) {
+
+        arrowKeys.forceActiveFocus()
+
+        // A double-click should select the credential,
+        // then generate if needed and copy the code.
+        selected = modelData
+        selectedIndex = index
+        if (selected.code == null || isExpired(selected)) {
+            generate()
+        } else {
+            copy()
+        }
+    }
+
     function updateTrayVisability() {
         SysTrayIcon.visible = settings.closeToTray
         // When the tray option is enabled, closing the last window