TedPage: Emphasis Gridlines

I'm checking in a patch to add emphasis grid lines into the Inkscape grid.

While, I don't know that this is a killer feature, it is something that I've found annoying. It is a real pain to count grid lines if there is no easy reference. You'll notice that I also chose to the default color to be very discrete, I kinda like that. It is almost like subconcious counting of gridlines.