Node Sorting Operators

A set of MeshPoints must sometimes be sorted, usually to reduce a selection. SortingOperators are objects that can be used to execute this sorting operation.

`SortByX0()`	Sort by X0 in increasing order
`SortByY0()`	Sort by Y0 in increasing order
`SortByZ0()`	Sort by Z0 in increasing order
`SortByDX0()`	Sort by X0 in decreasing order
`SortByDY0()`	Sort by Y0 in decreasing order
`SortByDZ0()`	Sort by Z0 in decreasing order
`SortByPos0(lock)`	Sort in increasing order by an initial coordinate in a given direction (lock = TX, TY or TZ)
`SortByKsi0(curve)`	Project nodes on the curve then sort in increasing order by projected curve abscissa
`SortByDist0(x,y,z)`	Sort nodes by increasing distance from the point of coordinates (x,y,z)
`SortByNo()`	Sort nodes by increasing user number
`InverseSOp(sOp)`	Inverse the effect of the sorting operator to which it is applied
`CombineSOp(sOp1, Sop2)`	Combine 2 sortings Operators (applying SOp1 then SOp2)

Use:

Extracting curves (''valuesManager'')
Sorting groups (''Group'')