fix logging, to send error logs to stderr

add dependency plugin, and bump version 0.18.0

version 0.16.0

reduce logging to ERROR

else the logging appears in the output stream and breaks the xml.
it should be logging to stderr but doesn't appear to be doing so

version 0.14.1

flush the output stream when finished

reduced restriction on data validaty being gathered to only skip when…

… formula2 is empty

reduced restriction on data validaty being gathered to only skip when…

… formula2 is empty

uses the cached value and type for a formula cell, rather than reeval…

…uating the formula

updated to newer version of poi