[PD] [ANN] New External: tglgrid, a togglable grid of cells

[Nick Lanham]

Just FYI, I've pushed a fairly big update that adds the following features:

- an rtglgrid that operates row-wise
- messages to get cell, column and row state: "say col row", "csay col", 
and "rsay row"
- "size" message to dynamically re-size the grid
- a properties dialog where one can set cell size, spacing colors, and 
grid dimensions
- a more colorful and better organized help dialog :)

It should load your old saves fine, please let me know if it doesn't.

Hope people find this useful, and thanks for the feedback so far!

-Nick