fixes #146, text column for data in items table isn't appropiate
Correcting error message

set_cache_location() is mentioned twice, but set_cache_duration() is not mentioned at all.
Merge pull request #302 from rapid2k1/patch146

fixes #146, text column for data in items table isn't appropiate, default column datatype size isn't enough
Merge pull request #322 from joshlewis/patch-1

Correcting error message