Make revert direction functionality available from menu.
cadtoolbar for revertDirection
include svg icon for revertDirection
revertDirection tooltip in cadtoolbar fixed and icon added to menu
Polyline revertDirection implemented.
Splines revertDirection implemented.
hatch: intersection is not counted

Intersection with a start-/end point of a line of a contour with
an angle > pi is not counted (variable counter is not incremented).
For testing use file: https://github.com/smallfix/librecadbugfiles/blob/master/hatch/contour_counter.dxf
and the hatch pattern "hound".
Merge pull request #424 from smallfix/hatchfix2

Thanks!
Merge pull request #412 from effad/master

Make revert direction functionality available from menu.