Proposal to add standardized variation sequences for chess notation

[Michael Everson]

Variation Sequences have been implemented for a number of symbol characters recently to make them useful for specialized purposes.
 
Here is a proposal which solves a long-standing problem for an important set of symbols in the UCS.

https://www.dropbox.com/sh/p9vga1dc2t02pqw/AABL4XwI-ZERDbnLJmvJJvtja?dl=0

Enjoy,
Michael Everson