Remove some debug messages. Change some error messages..

Remove some useless debug messages, e.g. because they just print an SQL
string which you can see in the SQL log window anyway.

Change some "critical" errors messages to just warning. No sense in
printing a critical error message when the program can handle the
problem by itself.

src/sqltextedit.cpp

@@ -280,7 +280,7 @@ void SqlTextEdit::keyPressEvent(QKeyEvent *e)
         table = identifier.left(dotpos);
         field = identifier.mid(dotpos + 1);
     }
-//    qDebug() << identifier << ":" << table << ":" << field;
+
     if( dotpos > 0 )
     {
         // swap model to field completion