The move number now appears as you hover the Eval Line (about to click on a move) so you know which move you're clicking on

[yuzisee]

Summary

This is a simpler version of #235 containing only the Move Number / Token annotation, and without all the eval stuff.

Purpose

When hovering the mouse, show the move token of the move you are hovering over.

1. Make Analysis Easier:

• When Analysis is on, you might not want to change the actual move (or it will disrupt your analysis).
• However, you may still wish to investigate certain eval spikes while analysis continues to run on the rest of the game. This pull request lets you hover over whatever sections of the eval line are interesting to you and see which moves they correspond to, without having to click & disrupt the analysis itself.

2. Improve Usability:

• When you click on the eval line, in current master, you aren't ever really sure which move you'll get.
• This pull request helps users pinpoint specific moves that they are hoping to jump to before they click, by providing live feedback beside their cursor.