Fix for cleantable perl code & Link List

This fixes the Clean Table macro by 1) storing the selection to a new variable `MMD__Table` and then using that in the perl script instead of stdin.

I also updated the Clipboard Link List code to the current version from Brett Terpstra's library, where it originated, which takes care of the issues with Ruby > 1.9 and has some other fixes besides. It works great.

There are multiple commits because a) I just figured out how to do this,  b) I forgot to close all the descriptions before exporting, creating unnecessary changes, and c) I didn't know I had to create branches to create separate pull requests for each file/macro. Hopefully this is useful anyway.