todo: try to fix compile warmings due i not know what happened to qt5

[mckaygerhard]

the compilation seems have some warnings:

In file included from src/eggwm/EggWM.cpp:17:0:
src/eggwm/EggWM.h:31:54: warning: unused parameter ‘eventType’ [-Wunused-parameter]
     virtual bool nativeEventFilter(const QByteArray &eventType, void *message, long *) Q_DECL_OVERRIDE

src/eggwm/standards/ICCCM.cpp: In member function ‘void ICCCM::sendProtocol(const char*) const’:
src/eggwm/standards/ICCCM.cpp:91:72: warning: passing NULL to non-pointer argument 4 of ‘int XSendEvent(Display*, Window, int, long int, XEvent*)’ [-Wconversion-null]
     XSendEvent(QX11Info::display(), this->clientID, false, NULL, &event);

src/eggwm/atoms/AtomList.cpp: In member function ‘Atom AtomList::getAtom(const char*)’:
src/eggwm/atoms/AtomList.cpp:148:48: warning: passing NULL to non-pointer argument 2 of ‘const T QHash<Key, T>::value(const Key&, const T&) const [with Key = const char*; T = long unsigned int]’ [-Wconversion-null]
     return this->atomHash->value(atomName, NULL);