Both JdbcResultSet and JdbcCallableStatement currently do not support
getObject(int, Class) and getObject(String, Class) but support is easy
to add.

This commits contains the following changes:

 - add support for getObject(int, Class) and getObject(String, Class)
    with the following types: BigDecimal, String, Boolean, Byte, Short,
   Integer, Long, Float, Double, Date, Time, Timestamp, UUID,
   TimestampWithTimeZone and Geometry subclasses
 - extend the existing getObject tests to cover these new methods

Most notably missing is support for LOBs and arrays including primitive
arrays but this can always be added later.