dissimilarity.py missing from methods folder

[JackyZzZz]

I noticed that we need to import dissimilarity.py from methods in the Running Dissimilarity Algorithms example in the documentation. However, it seems like this file is missing from the methods folder.

P.S: I think it is renamed to distance.py, so we should probably update the documentation.

Add-on:

• the first parameter of select function in base.py is X, not arr in the documentation

[FanwangM]

Thank for noticing this.
I will do a cleaning up after May 31st, and we can probably talk about it in our next meeting. @JackyZzZz