Add an initial implementation of optics
Remove optics personal implementation
Refactor Amy X Zhang clustering algorithm
Add original order in TreeNode class as attribute
Fix error related to OPTICS move refactor
Use leave.points instead of start / end.
Add function order_reach_plot
Add reachability chart
Small fix
Merge branch 'master' of github.com:GenosResearchGroup/FlautaSolo

# Please enter a commit message to explain why this merge is necessary,
# especially if it merges an updated upstream into a topic branch.
#
# Lines starting with '#' will be ignored, and an empty message aborts
# the commit.
Add clusters table