Add a name accessor to Type

Also fix up some misentered type info and add a test to ensure it's
correct.

Author: sfackler

src/lib.rs

@@ -665,7 +665,7 @@ impl InnerConnection {
     }
 
     fn get_type(&mut self, oid: Oid) -> Result<Type> {
-        if let Some(ty) = Type::new(oid) {
+        if let Some(ty) = Type::from_oid(oid) {
             return Ok(ty);
         }
 
@@ -1353,10 +1353,6 @@ trait DbErrorNew {
     fn new<T>(fields: Vec<(u8, String)>) -> Result<T>;
 }
 
-trait TypeNew {
-    fn new(oid: Oid) -> Option<Type>;
-}
-
 trait RowsNew<'a> {
     fn new(stmt: &'a Statement<'a>, data: Vec<Vec<Option<Vec<u8>>>>) -> Rows<'a>;
 }