Allow a command line argument for wt that would accept a monitor designation

# Description of the new feature/enhancement

I have not found a way to cause a new invocation of wt to position its window onto the monitor of my choice.

Things I have tried:
1) Manually drag the wt window to my chosen monitor. Close it and start a new wt instance. Other windows respect the Windows settings (System->Display) 'Remember window locations based on monitor connection'. But the wt window does not appear to honor that.
2) For 'wt --pos ', set x and y to various values. This works, but only puts the window on the 'main display' monitor.
Note that for giggles, I tried negative numbers and this caused the window to appear on the other(not main) display monitor, but always at position <0,0>.

# Proposed technical implementation details (optional)

Suggestions for possible implementation:
*) Allow another command line arg, perhaps similar to the Linux '--display'.
*) Allow the current args of --pos to include an optional monitor number, such as <1:100,100>
*) Honor, the 'Remember window locations based on monitor connection' setting. BUT, allow --pos to override that.

Start by tracing how the wt command-line entry point handles --pos and how window placement interacts with the Windows display setting described in the issue. The work is complete when one agreed monitor-selection interface is implemented, --pos behavior is defined, and the setting-versus-override behavior is verified.

Written by the indexing model from the issue text.