Doubleclick sometimes selects wrong units

[elexis]

Following ​Phab:D326

Reproduce 1:

1. single-click on a unit (lasso selection starting on the ground won't do it)
2. click on a building in the construction panel and move the mouse cursor to a place where we can place the foundation
3. double click (both clicks must occur before the foundation is placed. So this is easier to reproduce with a great turn length (500ms MP, 200ms SP) (Press F9 and type Engine.SetTurnLength(1000); in MP to make it even easier)

Result: all women are selected

Reproduce 2:

1. have some fields and a woman standing on those fields
2. move the mouse cursor over the field and select the woman with the lasso selection (the mousedown goes on the field without actually selecting it)
3. same last two steps as above

Result: all fields are selected

[elexis]

In 19786:

Prevent unintentional selection of all units following rP19444 / D326 when doubleclicking while not in selection input mode.

Differential Revision: ​https://code.wildfiregames.com/D634
Fixes #4631.
Refs #4414.
Patch By: causative