fix(file-list): ensure patterns are comparable

Thanks to @m-a-r-c-e-l-i-n-o for pointing me in the right direction
Fixes #2194

lib/file-list.js

@@ -20,6 +20,7 @@ var File = require('./file')
 var Url = require('./url')
 var helper = require('./helper')
 var log = require('./logger').create('watcher')
+var createPatternObject = require('./config').createPatternObject
 
 // Constants
 // ---------
@@ -230,6 +231,13 @@ Object.defineProperty(List.prototype, 'files', {
     var lookup = {}
     var included = {}
     this._patterns.forEach(function (p) {
+      // This needs to be here sadly, as plugins are modifiying
+      // the _patterns directly resulting in elements not being
+      // instantiated properly
+      if (p.constructor.name !== 'Pattern') {
+        p = createPatternObject(p)
+      }
+
       var bucket = expandPattern(p)
       bucket.forEach(function (file) {
         var other = lookup[file.path]