Index rows from one by default

CHANGES.md

docs/scripting-api.rst

src/app/clipboardserver.cpp

src/common/appconfig.h

src/gui/clipboardbrowser.cpp

src/gui/clipboardbrowsershared.h

src/gui/configurationmanager.cpp

src/gui/mainwindow.cpp

src/gui/traymenu.cpp

src/gui/traymenu.h

src/item/itemdelegate.cpp

src/scriptable/scriptableproxy.cpp

src/tests/tests.cpp