GH-106 Implement PreparedStatement::get/setObject methods

PreparedStatement::getXXX() methods will attempt to convert resultset
 objects to requested type.
PreparedStatement::setXXX() methods will attempt to convert input parameters
 to given type as represented by ECL.
SetNULL will result in exception since ECL does not represent NULL value
Input parameters passed in to CALL statements will be serialized to string
and urlencoded before they're sent to HPCC.
Erroneous log statements in PreparedStatement fixed.

Signed-off-by: Rodrigo Pastrana <Rodrigo.Pastrana@lexisnexis.com>