Spinbox: don't ignore double clicks.
Spinbox: don't ignore double clicks.

Fixes the problem with spinboxes not updating when clicking too fast.

(cherry picked from commit dd4c2709e4a4f1abef558c5b3a4e4454db06410d)

pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1,pixelpicosean/my-godot-2.1