Added "doomthingrotationangles" Game Configuration property. When enabled, editor actions related to changing thing angle will snap the resulting angle to 45 degree increments. This property is set to true for vanilla game configurations.
Fixed a crash when changing game configuration from one without Thing actions support to one with them while in Things mode.
Fixed, cosmetic, DB2 bug: current editing mode button was deselected after reloading resources.
Updated documentation ("Game Configuration - Basic Settings" page).
Fixed, Visual mode: alpha-based texture picking didn't work correctly on HiRes images.
Fixed, Visual mode: fog density was calculated incorrectly for things lit by dynamic lights.
Fixed, Edit Sector window, UDMF: "Fade" and "Light" color pickers initial values were incorrect when displaying mixed values.
Fixed, Edit Thing window, UDMF: "Color" color picker initial value was incorrect when displaying mixed values.
