Add lru-cache dependency; make remote._received_tx an lru-cache with specified max length

package.json

@@ -12,10 +12,11 @@
     "test": "test"
   },
   "dependencies": {
-    "async": "~0.2.9",
+    "async": "~0.2.10",
     "ws": "~0.4.31",
     "extend": "~1.2.1",
-    "jshint-loader": "~0.5.0"
+    "jshint-loader": "~0.5.0",
+    "lru-cache": "~2.5.0"
   },
   "devDependencies": {
     "grunt": "~0.4.1",
@@ -26,7 +27,7 @@
     "grunt-dox": "~0.5.0",
     "mocha": "~1.14.0",
     "sinon-chai": "~2.4.0",
-    "sinon":"~1.7.3"
+    "sinon": "~1.7.3"
   },
   "scripts": {
     "pretest": "node_modules/.bin/grunt",

src/js/ripple/remote.js

@@ -15,6 +15,7 @@
 
 var EventEmitter = require('events').EventEmitter;
 var util         = require('util');
+var LRU          = require('lru-cache');
 var Request      = require('./request').Request;
 var Server       = require('./server').Server;
 var Amount       = require('./amount').Amount;
@@ -101,7 +102,7 @@ function Remote(opts, trace) {
   this._connection_offset    = 1000 * (typeof opts.connection_offset === 'number' ? opts.connection_offset : 5)
   this._submission_timeout   = 1000 * (typeof opts.submission_timeout === 'number' ? opts.submission_timeout : 10)
 
-  this._received_tx          = { };
+  this._received_tx          = LRU({ max: 10 });
   this._cur_path_find        = null;
 
   // Local signing implies local fees and sequences