ui: Added plain text editing dialog to list boxes in project setup UI

* Added class QtTextEditDialog for displaying text content
* Added edit button to QtDirectoryListBox
* Replaced show files button dialog using QtProjectWizzardContentSourceList with QtTextEditDialog

bin/app/data/gui/window/listbox.css

@@ -34,7 +34,7 @@ QtListItemWidget #field {
 	border-top: 1px solid lightgray;
 }
 
-#plusButton, #minusButton, #dotsButton {
+#plusButton, #minusButton, #dotsButton, #editButton {
 	color: white;
 	height: 1em;
 	margin-right: 3px;
@@ -70,6 +70,15 @@ QtListItemWidget #field {
 	border-image: url(<setting:gui_path>window/dots_hover.png);
 }
 
+#editButton {
+	border-image: url(<setting:gui_path>code_view/images/edit.png);
+	margin-left: 6px;
+}
+
+#editButton:hover {
+	background-color: #EEE;
+}
+
 #dropInfo {
 	color: #999;
 }

bin/app/data/gui/window/window.css

@@ -160,7 +160,7 @@
 	background: #CFD2E0;
 }
 
-#files {
+#textField {
 	border: 1px solid lightgray;
 	border-radius: 12px;
 	padding: 6px;