Debugger: Compile with QT_NO_CAST_FROM_ASCII.

(except gdbmi.cpp, name_demangler.cpp). Remove some unneeded
conversions, change some maps to take QByteArray keys.

Change-Id: I010f1251998a441fe5c8c87901b1e0c277c0391c
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/debugger/sourcefileshandler.cpp

@@ -61,8 +61,8 @@ QVariant SourceFilesHandler::headerData(int section,
 {
     if (orientation == Qt::Horizontal && role == Qt::DisplayRole) {
         static QString headers[] = {
-            tr("Internal name") + "        ",
-            tr("Full name") + "        ",
+            tr("Internal name") + QLatin1String("        "),
+            tr("Full name") + QLatin1String("        "),
         };
         return headers[section];
     }