Change doc theme to 'nature'.
Change doc theme to 'nature'.

technige/py2neo,fpieper/py2neo,nicolewhite/py2neo,nicolewhite/py2neo,nigelsmall/py2neo,nigelsmall/py2neo,technige/py2neo,fpieper/py2neo,nicolewhite/py2neo,fpieper/py2neo,technige/py2neo