Bitcoin-Qt: massive header and cpp cleanup

- try to enforce the same style to all Qt related files
- remove unneeded includes from the files
- add missing Q_OBJECT, QT_BEGIN_NAMESPACE / QT_END_NAMESPACE
- prepares for a pull-req to include Qt5 compatibility

Conflicts:
	src/qt/bitcoinaddressvalidator.h
	src/qt/notificator.cpp
	src/qt/optionsmodel.cpp
	src/qt/paymentserver.cpp