Modified and new markers, precision arrows

Hello,

in technical drawings like this

http://kf.fyz.fce.vutbr.cz/pub/inkscape/vykres-viko.png

it is often needen to make arrows and dimensions. In
inkscape there are suitable line-end-markers
"DimensionIn" and "DimensionOut". But there are two
problems which make it hard for real use. I tried to
demonstrate it on this figure:

http://kf.fyz.fce.vutbr.cz/pub/inkscape/arrows_old_3.png

- The node positions do not correspond to real ends of
the arrows

- The DimensionIn and DimensionOut append a little
perpendicular line to the arrow. Sometimes this line is
not needed. Unfortunately, other arrows are of
different shape so it looks ugly to mix "DimensionIn"
and ArrowL (bigger) or ArrowM (smaller).

So I modified the markers.svg, changed (and simplified)
the DimensionIn and DimensionOut so that the arrow tips
correspond to node positions.
Moreover, I added another arrow shapes - ArrowIn and
ArrowOut. As you can see on this picture

http://kf.fyz.fce.vutbr.cz/pub/inkscape/arrows_new.png

It is now very easy to make dimensions if snap to grid
is activated. Another advantage is that now there are
two type of arrows of the same shape with or without
the perpendicular line.

The arrows/dimensions can now very easily be chained to
make something like

|<----->|<----->|<----->|<---------->|
| | | | |

I am sending you the modified file with markers.

bye
Jan Martinek