Problem: zchunk_new is badly documented
Problem: 'n' for zero-sized frame isn't obvious

Solution: use 'z' instead
Problem: zdir always loads entire tree

Solution: if parent path is specified as "-", load only top level.
Merge pull request #650 from hintjens/master

Allow zdir to load top level only
Problem: zsock_option.c:78 fails on MSVC

Some confusion in the code, passing a polymorphic socket reference to a
method that accepts only zsock_t *.

Solution: change zsock_type_str() to accept a polymorphic reference and
resolve properly to get the socket type.
Merge pull request #651 from hintjens/master

Problem: zsock_option.c:78 fails on MSVC