in hayooCrawler minor changes
in hayooCrawler and searchengine the EnumMap substituted with a simple Data.IntMap.Strict

EnumMap does not support all strict operations needed, this led to space leaks
in the crawler (and in the search engine)
Binary instance for Text moved into extra file Data.Text.Binary
example for using Reader and Error monad and command interpretation in a server added in test/ExampleServer