Improve scrolling, add comments in header files

ChangeLog

TODO

src/call.cpp

src/call.h

src/gui/qt/jpushbutton.cpp

src/gui/qt/jpushbutton.h

src/gui/qt/mydisplay.cpp

src/gui/qt/mydisplay.h

src/gui/qt/phoneline.cpp

src/gui/qt/phoneline.h

src/gui/qt/qtGUImainwindow.cpp

src/gui/qt/qtGUImainwindow.h

src/gui/qt/transqwidget.cpp

src/gui/qt/transqwidget.h

src/gui/qt/volumecontrol.cpp

src/managerimpl.h