#8 create a chain of parents for files

[Artem Vasiliev]

create a chain of parents for index root that is not a
directory root on a host, e.g. if index root like
"\\me\distr\video" is specified "\", "\distr" and
"\distr\video" files should be created. This is
necessary for "parents" field to be consistent when
index is created first from "\\me\distr\video" then
extended to "\\me\distr" and will make handling of this
situation easier and less consuming.

[Artem Vasiliev]

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Also provide unit tests for such situation (currently absent)