Sorafenib Completed Phase 2 Trials for Neuroendocrine Tumors / Gastrinoma / Glucagonoma / Metastatic Gastrointestinal Carcinoid Tumor / Recurrent Gastrointestinal Carcinoid Tumor / WDHA Syndrome / Pancreatic Polypeptide Tumor / Recurrent Islet Cell Carcinoma / Insulinoma / Somatostatinoma Treatment