C++: change working-copy to work on UTF-8 encoded QByteArrays.

These not only take less space than UTF-16 encoded QStrings, but due to
the caching in the CppEditorSupport also take less time to build.

This patch also fixes a number of possible encoding issues, where files
and constant strings were (falsely) assumed to be UTF-8.

Change-Id: Ib6f91c9a94ebed5b5dfbd4eb2998825c62c72784
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/cpptools/cppsemanticinfo.h

@@ -47,7 +47,7 @@ public:
     {
         const CPlusPlus::Snapshot snapshot;
         const QString fileName;
-        const QString code;
+        const QByteArray code;
         const int line;
         const int column;
         const unsigned revision;
@@ -59,7 +59,7 @@ public:
 
         Source(const CPlusPlus::Snapshot &snapshot,
                const QString &fileName,
-               const QString &code,
+               const QByteArray &code,
                int line, int column,
                unsigned revision,
                bool force)