Removed cache object.

Fixes #2.

After thinking about this, I thought the best approach was to remove the cache object. This keeps the encode and decode functions focused on a single responsibility.

lib/encdec.js

@@ -5,8 +5,7 @@
     var BASE_58 = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ';
 
     alphabet = alphabet || BASE_58;
-    var baseCount = alphabet.length,
-        cache = {};
+    var baseCount = alphabet.length;
 
     return {
       encode : function(num) {
@@ -19,10 +18,6 @@
           return '';
         }
 
-        if (cache[num]) {
-          return cache[num];
-        }
-
         var encode = '';
 
         while (num >= baseCount) {
@@ -35,7 +30,6 @@
           encode = alphabet[num] + encode;
         }
 
-        cache[num] = encode;
         return encode;
       },
 
@@ -44,10 +38,6 @@
           return 0;
         }
 
-        if (cache[s]) {
-          return cache[s];
-        }
-
         var decoded = 0,
             multi = 1,
             reversed = s.split('').reverse().join('');
@@ -57,7 +47,6 @@
           multi = multi * baseCount;
         }
 
-        cache[s] = decoded;
         return decoded;
       }
     };