Depending on the input mode, either `Growth` or `Angle` is used to create
a conical or flat spiral. The respective other can easily be calculated
to give consistent view. This is already done for the other properties,
e.g. `Height` is calculated from `Pitch` and `Turns`.
With this patch, the same is done for `Angle` and `Growth`.
- when a helix is defined in the growth mode it can have a pitch of zero
This commit fixes the resulting division by zero by directly setting the known turns
Introduce an enum to verify the axis depending on the used context.
* For helix no restriction is needed
* For Pad/Pocket the axis must not be parallel with the sketch plane
* For Revolve/Groove the axis must not be perpendicular with the sketch plane
Helices that become smaller with every turn are geometrically perfectly valid. Therefore we cannot forbid this.
(For example when creating a helix from a face you often cannot move it so that you can apply a positive growth.)
Now that we have the feature that sweeps can have vertices as end or begin of a sweep, there is the need for the feature to move sections. For example vertices may only be the last section.
- it is not sensible that all helix geometries use 1 as increment in the dialog but the growth uses 5. Looking at the PR that introduced this feature it seems that this was just a copy issue from the angle edit since this uses 5 as increment.
- the other changes are from Qt's Designer
Previously, only the vertical and horizontal axis of the profile was
selectable in the task panel of the additive/subtractive helix. Now the
profile's normal axis can be selected, too. This now allows to create
helical extrusions or "twisted pockets".
The order of the GUI entries was chosen to be in line with the order of
axis selection of the multi-transform parameters.
The actual feature's implementation needed adaption for this special case
as in some places a unit vector (`gp_Dir`) was derived from the cross-
product of axis and profile normal -- a null-vector when the axis *is*
the normal. This caused the gp_Dir's ctor to throw.
