Allow multiple classifications.

BotSharp.NLP.UnitTest/NaiveBayesClassifierTest.cs

@@ -45,7 +45,7 @@ namespace BotSharp.NLP.UnitTest
             testData.ForEach(td =>
             {
                 var classes = classifier.Classify(td);
-                if(td.Label == classes[0].Item1)
+                if(td.Labels[0] == classes[0].Item1)
                 {
                     correct++;
                 }

BotSharp.NLP/Classify/ClassifierFactory.cs

@@ -38,7 +38,7 @@ namespace BotSharp.NLP.Classify
         {
             _classifier.Train(sentences.Select(x => new LabeledFeatureSet
             {
-                Label = x.Label,
+                Label = x.Labels[0],
                 Features = GetFeatures(x.Words)
             }).ToList(), _options);
         }

BotSharp.NLP/Corpus/LabeledPerFileNameReader.cs

@@ -26,7 +26,7 @@ namespace BotSharp.NLP.Corpus
                     {
                         sentences.Add(new Sentence
                         {
-                            Label = lable,
+                            Labels = new List<string> { lable },
                             Text = line
                         });
                     }

BotSharp.NLP/Sentence.cs

@@ -9,7 +9,10 @@ namespace BotSharp.NLP
     {
         public List<Token> Words { get; set; }
 
-        public String Label { get; set; }
+        /// <summary>
+        /// Allow multiple classification
+        /// </summary>
+        public List<String> Labels { get; set; }
 
         public String Text { get; set; }
     }