=================================================================
Common utility functions used by almost all Command classes were previous in Constraint.h.
Aside from providing a very bad intent, it created unnecessary header dependencies.
This commit separates these common functions into a new header, utils.h, which is then
used in all command classes where it is necessary.
===============================================
It is a long felt need that redundant constraints are not generated while autoconstraining.
The solver sketcher in v0.17 is überpicky with redundants due to the new popularity contest algorithm. The former behaviour is exhacerbated.
This new mode enables automatic redundant constraint removal.
In UI operations IN EDIT MODE, upon detection of redundancy by the solver, the Sketcher will remove all redundant constraints detected by that solve.
This makes the sketcher much less annoying.
How to test this?
The easiest example is to create a vertical line. Then make the endpoints symmetric with respect to the horizontal axis. Without this mode,
the vertical constraint and the symmetry constraint are redundant. With this mode, the vertical constraint gets automatically removed by the Sketcher.
======================================================================
The switch virtual space toolbar button operated just to switch from one virtual space to the other (without any element selected), so switching the "mode".
Now if there is a selection, all the constraints are moved to the alternative virtual space.
It works similar to the toggle buttons for geometry elements and constraints
