Fix invalid metadata on delete.
Refactoring.
Merge pull request #6 from nbeloglazov/fix-meta-on-delete

Fix meta on delete
Release 1.1.2 to include bugfix from #6.
Add benchmarking.
Optimize nearest neighbor function.
Optimize nearest neighbor.
REfactoring. Fix invalid meta retaining on delete.
Move bencharmking dependencies to :dev profile.
Optimize find-min function.
Remove unused depth field from Node record.
Optimize delete and insert.
Fix bench.
Merge.