DOSet and Hashmap implemented; not tested; infra methods missing
infra methods added; set iteration missing
WIP on set iterator
major remodeling; aim to support HS-based infrastructures only; removed anntations; simplified interface to infrastructure class
implemented do set iteration
subelement-of references for doset members fixed
fixing bugs in handle infrastructure due to remodeling
fixed bad unicode/str compare
bugfixes when removing hash/doset elements