Improve error handling

Added individual error classes
Don't silently fail for commands without callback from now on
General polishing (e.g. better error messages)

Fix typos

lib/customErrors.js

@@ -0,0 +1,78 @@
+'use strict';
+
+var util = require('util');
+
+function AbortError (obj) {
+    Error.captureStackTrace(this, this.constructor);
+    var message;
+    Object.defineProperty(this, 'name', {
+        get: function () {
+            return this.constructor.name;
+        }
+    });
+    Object.defineProperty(this, 'message', {
+        get: function () {
+            return message;
+        },
+        set: function (msg) {
+            message = msg;
+        }
+    });
+    for (var keys = Object.keys(obj), key = keys.pop(); key; key = keys.pop()) {
+        this[key] = obj[key];
+    }
+    // Explicitly add the message
+    // If the obj is a error itself, the message is not enumerable
+    this.message = obj.message;
+}
+
+function ReplyError (obj) {
+    Error.captureStackTrace(this, this.constructor);
+    var tmp;
+    Object.defineProperty(this, 'name', {
+        get: function () {
+            return this.constructor.name;
+        }
+    });
+    Object.defineProperty(this, 'message', {
+        get: function () {
+            return tmp;
+        },
+        set: function (msg) {
+            tmp = msg;
+        }
+    });
+    this.message = obj.message;
+}
+
+function AggregateError (obj) {
+    Error.captureStackTrace(this, this.constructor);
+    var tmp;
+    Object.defineProperty(this, 'name', {
+        get: function () {
+            return this.constructor.name;
+        }
+    });
+    Object.defineProperty(this, 'message', {
+        get: function () {
+            return tmp;
+        },
+        set: function (msg) {
+            tmp = msg;
+        }
+    });
+    for (var keys = Object.keys(obj), key = keys.pop(); key; key = keys.pop()) {
+        this[key] = obj[key];
+    }
+    this.message = obj.message;
+}
+
+util.inherits(ReplyError, Error);
+util.inherits(AbortError, Error);
+util.inherits(AggregateError, AbortError);
+
+module.exports = {
+    ReplyError: ReplyError,
+    AbortError: AbortError,
+    AggregateError: AggregateError
+};