[GRASS5] Improvements to gis.m map canvas

[Glynn Clements]

Cedric Shock wrote:

> There is still one "after" in MapCanvas::mapsettings after running "d.mon 
> stop=gism" to "wait to make sure that the driver is shut down". This is 
> probably extraneous, but I'm not sure since the R_ commands seem to just push 
> messages off to another process. If it's not needed we can shave a nice 
> big .5 seconds off many redraws.

It shouldn't be necessary; I changed R_kill_driver() so that it
doesn't return until the driver has actually terminated.

Also, it should only be necessary to restart the driver if the image
dimensions are changed; changing the region shouldn't require a
restart.

-- 
Glynn Clements <glynn at gclements.plus.com>