social_snippet: test: add snippet snippets case (issue #33)
social_snippet: test: add snippet snippet ... snippet case (issue #33)
social_snippet: test: add snip self directly case (issue #33)
social_snippet: fix snip-self directly case
social_snippet: test: add snip-self indirectly case (issue #33)
social_snippet: fix snip self indirectly case
social_snippet: test: add use parent path case (issue #33)
social_snippet: fix using parent path case
social_snippet: test: add version up case (issue #13, #33)