Add setting to Select widget to allow single-point click to select only the topmost feature

[chrisclaydon]

The Select widget currently performs deep selection even when the user clicks on a single point (as opposed to dragging a rectangle). Users have requested that a single click only return the topmost feature, as is common in other applications.

A new parameter, PointClickSingleSelect, will be added to the Select widget to allow the behaviour to be controlled. If set to true, only the topmost feature will be selected. If set to false, any features below the clicked point will be selected, up to the value of the MaxFeatures setting.

[chrisclaydon]

(In [1753]) re #204 - Submission to fusion-mg21 branch: Add setting to Select widget to allow single-point click to select only the topmost feature

[chrisclaydon]

(In [1756]) Fix #204 - Submission to trunk for: Add setting to Select widget to allow single-point click to select only the topmost feature