[add code generation for FPwr and FAtan2
John Meacham <john@repetae.net>**20080312031859] hunk ./C/FromGrin2.hs 614
+    | Just fn <- Op.binopFunc ta tb n = return $ functionCall (toName fn) [a,b]
hunk ./C/Op.hs 308
+binopFunc :: Ty -> Ty -> BinOp -> Maybe String
+binopFunc (TyBits b _) _ bop = g b =<< f bop where
+    g (Bits 64) x = return x
+    g (Bits 32) x = return $ x ++ "f"
+    g _ _ = Nothing
+    f FPwr = Just "pow"
+    f FAtan2 = Just "atan2"
+    f _ = Nothing