Update fixnum to new package guidelines.

pkg/fixnum/lib/src/int64.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of fixnum;
 
 /**
  * An immutable 64-bit signed integer, in the range [-2^63, 2^63 - 1].
  * Arithmetic operations may overflow in order to maintain this range.
  */
@@ skipping 171 matching lines @@
     }
 
     if (negative) {
       _l = ~_l & _MASK;
       _m = ~_m & _MASK;
       _h = ~_h & _MASK_2;
     }
   }
 
   factory int64.fromBytes(List<int> bytes) {
-    int top = bytes[7] & 0xff; 
+    int top = bytes[7] & 0xff;
     top <<= 8;
     top |= bytes[6] & 0xff;
     top <<= 8;
     top |= bytes[5] & 0xff;
     top <<= 8;
     top |= bytes[4] & 0xff;
 
-    int bottom = bytes[3] & 0xff; 
+    int bottom = bytes[3] & 0xff;
     bottom <<= 8;
     bottom |= bytes[2] & 0xff;
     bottom <<= 8;
     bottom |= bytes[1] & 0xff;
     bottom <<= 8;
     bottom |= bytes[0] & 0xff;
 
     return new int64.fromInts(top, bottom);
   }
 
   factory int64.fromBytesBigEndian(List<int> bytes) {
-    int top = bytes[0] & 0xff; 
+    int top = bytes[0] & 0xff;
     top <<= 8;
     top |= bytes[1] & 0xff;
     top <<= 8;
     top |= bytes[2] & 0xff;
     top <<= 8;
     top |= bytes[3] & 0xff;
 
-    int bottom = bytes[4] & 0xff; 
+    int bottom = bytes[4] & 0xff;
     bottom <<= 8;
     bottom |= bytes[5] & 0xff;
     bottom <<= 8;
     bottom |= bytes[6] & 0xff;
     bottom <<= 8;
     bottom |= bytes[7] & 0xff;
 
     return new int64.fromInts(top, bottom);
  }
 
@@ skipping 220 matching lines @@
     n &= 63;
 
     int res0, res1, res2;
 
     // Sign extend h(a).
     int a2 = _h;
     bool negative = (a2 & _SIGN_BIT_VALUE) != 0;
     if (negative) {
       a2 += 0x3 << _BITS2; // add extra one bits on the left
     }
-    
+
     if (n < _BITS) {
       res2 = _shiftRight(a2, n);
       if (negative) {
         res2 |= _MASK_2 & ~(_MASK_2 >> n);
       }
       res1 = _shiftRight(_m, n) | (a2 << (_BITS - n));
       res0 = _shiftRight(_l, n) | (_m << (_BITS - n));
     } else if (n < _BITS01) {
       res2 = negative ? _MASK_2 : 0;
       res1 = _shiftRight(a2, n - _BITS);
@@ skipping 616 matching lines @@
         }
       }
       return ZERO;
     }
 
     // Generate the quotient using bit-at-a-time long division.
     return _divModHelper(aIsCopy ? a : new int64._copy(a), b, negative,
         aIsNegative, aIsMinValue, computeRemainder);
   }
 }