Add instance copying, fix instance creation (with identical names)

gui/mainwindow.ui

@@ -62,6 +62,8 @@
     <bool>false</bool>
    </attribute>
    <addaction name="actionAddInstance"/>
+   <addaction name="actionCopyInstance"/>
+   <addaction name="separator"/>
    <addaction name="actionViewInstanceFolder"/>
    <addaction name="actionViewCentralModsFolder"/>
    <addaction name="actionRefresh"/>
@@ -310,6 +312,9 @@
    <property name="statusTip">
     <string>Change the selected instance's icon.</string>
    </property>
+   <property name="iconVisibleInMenu">
+    <bool>true</bool>
+   </property>
   </action>
   <action name="actionEditInstNotes">
    <property name="text">
@@ -445,6 +450,21 @@
     <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p align=&quot;center&quot;&gt;&lt;span style=&quot; font-weight:600; color:#ff0004;&quot;&gt;Catnarok!&lt;/span&gt;&lt;/p&gt;&lt;p align=&quot;center&quot;&gt;Or just a cat with a ball of yarn?&lt;/p&gt;&lt;p align=&quot;center&quot;&gt;&lt;span style=&quot; font-style:italic;&quot;&gt;WHO KNOWS?!&lt;/span&gt;&lt;/p&gt;&lt;p align=&quot;center&quot;&gt;&lt;img src=&quot;:/icons/instances/tnt&quot;/&gt;&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
    </property>
   </action>
+  <action name="actionCopyInstance">
+   <property name="icon">
+    <iconset resource="../multimc.qrc">
+     <normaloff>:/icons/toolbar/copy</normaloff>:/icons/toolbar/copy</iconset>
+   </property>
+   <property name="text">
+    <string>Copy Instance</string>
+   </property>
+   <property name="toolTip">
+    <string>Copy the selected instance.</string>
+   </property>
+   <property name="statusTip">
+    <string>Add a new instance.</string>
+   </property>
+  </action>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
  <resources>