Fixed, Visual mode, Auto-align actions: incorrect texture was used when...

Fixed, Visual mode, Auto-align actions: incorrect texture was used when clamping texture offsets of 3D floor sides.
Fixed, Numeric textbox: incorrect character was treated as decimal separator character was used when using certain Windows regional settings.
Changed, Edit Things window: when applicable, the "Filter" textbox is now focused when opening the window.
Changed, Sector Effects browser window: when applicable, the "Filter" textbox is now focused when opening the window.
Changed, Edit Things window: when the "Filter" textbox is focused, pressing the "Down" key will now switch focus to the Things list.
Changed, Sector Effects Browser window: when the "Filter" textbox is focused, pressing the "Down" key will now switch focus to the Effects list.
Changed, Linedef Action Browser window: when the "Filter" textbox is focused, pressing the "Down" key will now switch focus to the Actions list.
Configurations, Doom map format thing flags: changed "Multiplayer" flag name to "Multiplayer only".