Merge pull request #647 from awerlang/patch-1

print empty string instead of undefined or null

lib/mixins/text.coffee

@@ -23,7 +23,7 @@ module.exports =
     options = @_initOptions(x, y, options)
 
     # Convert text to a string
-    text = '' + text
+    text = if not text? then '' else '' + text
 
     # if the wordSpacing option is specified, remove multiple consecutive spaces
     if options.wordSpacing