Rework inspect-value to recursively invoke itself on collection elements

Old `inspect-value` failed on small sequences (up to 5 elements) that
contained huge collections. They were printed via `pr-str` and blew
off the memory limit. This commit removes the issue and allows to
safely display collections (partly or fully) even if they contain
other collections.
Merge pull request #3 from alexander-yakushev/safe-print

Rework inspect-value to recursively invoke itself on collection elements