Utilize fewer reexports

In regards to:

rust-lang/rust#19253 (comment)

This commit:

* Changes the #deriving code so that it generates code that utilizes fewer
  reexports (in particur Option::* and Result::*), which is necessary to
  remove those reexports in the future
* Changes other areas of the codebase so that fewer reexports are utilized

map.rs

@@ -25,8 +25,10 @@ use kinds::Sized;
 use mem::{mod, replace};
 use num::{Int, UnsignedInt};
 use ops::{Deref, Index, IndexMut};
-use option::{Some, None, Option};
-use result::{Result, Ok, Err};
+use option::Option;
+use option::Option::{Some, None};
+use result::Result;
+use result::Result::{Ok, Err};
 
 use super::table;
 use super::table::{

set.rs

@@ -19,8 +19,8 @@ use fmt;
 use hash::{Hash, Hasher, RandomSipHasher};
 use iter::{Iterator, IteratorExt, FromIterator, FilterMap, Chain, Repeat, Zip, Extend, repeat};
 use iter;
-use option::{Some, None};
-use result::{Ok, Err};
+use option::Option::{Some, None};
+use result::Result::{Ok, Err};
 
 use super::map::{HashMap, Entries, MoveEntries, INITIAL_CAPACITY};
 

table.rs

@@ -21,7 +21,8 @@ use mem::{min_align_of, size_of};
 use mem;
 use num::{Int, UnsignedInt};
 use ops::{Deref, DerefMut, Drop};
-use option::{Some, None, Option};
+use option::Option;
+use option::Option::{Some, None};
 use ptr::{RawPtr, copy_nonoverlapping_memory, zero_memory};
 use ptr;
 use rt::heap::{allocate, deallocate};