A Phase II, Open-Label, Randomized, Multicenter Trial of Pazopanib (GW786034) in Combination with Lapatinib (GW572016) Compared to Pazopanib Monotherapy and Lapatinib Monotherapy in Subjects with International Federation of Gynecology (FIGO) Stage IVB or Recurrent or Persistent Cervical Cancer with Zero or One Prior Chemotherapy Regimen for Advanced/Recurrent Disease