remove obsolete test for Data::Partition id attribute
add test for Data::Partition->new()
update test for Data::Partition type attribute
update test for Data::Partition begin attribute
update test for Data::Partition size attribute
update test for Data::Partition end attribute
update test for Data::Partition load()
update test for Data::Partition dump()
update test for Data::Partition clone()
add test for Data::Partition flags attribute
improve/extend/rework Data::Partition

 - new object constructor
 - support custom partition flags
 - removed 'id' attribute
 - removed ability to set dynamic attributes via constructor