Remove some q3ptrlist

I remove following q3ptrlist:
Move QPtrList in schematic.cpp to QVector
Move Q3PtrList in Dialogs/sweepdialog
Move Q3PtrList<QString> module: Categories
Move Q3PtrList<QString> HierarchyHistory in qucs 
Move Q3PtrList<subparameter> in painting/id_text 
Move Q3ValueList<DigiSignal> in schematic_file
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I think others are highly related to schematic and components, which will encounter some level of redesign during migrate to qt4, so I just leave them. I will focus on move q3scrollview to qt4 from now on.