CLI: Ignore blank lines

MarkovGrams/Program.cs

@@ -84,6 +84,9 @@ namespace MarkovGrams
 
 			IEnumerable<string> words = wordlistSource.ReadAllLines().SelectMany((string word) => {
 				word = word.Trim();
+				// No blank lines here!
+				if (string.IsNullOrWhiteSpace(word)) return new string[] { };
+
 				if (convertLowercase)
 					word = word.ToLower();
 				if (splitOnWhitespace)