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".
Fixed, Texture Browser Form: well, I broke "Tab" key functionality again (in previous commit)...
Maintenance: changed curly braces style to match DB2 one (hopefully not breaking anything in the process...).
Maintenance: changed private method names casing to match DB2 one.
Visual mode: real floor was colored by 3d floor's color even when it was below real floor.
Action Browser form: keyboard focus is now set to Filter text box by default.
Configurations: all 64 game configuration are now available by default.
Game Configurations window: game configurations can now be disabled. This setting is mostly cosmetic. When a game configuration is disabled, it won't be shown in "game configuration" dropdowns in New\Open Map Options and Map Options windows. If a map's .dbs file specifies a disabled configuration, it will be picked as a map configuration anyway.
Linedefs mode: vertex insert preview logic used Highlight range instead of Stitch range (which is used when draw mode engages).
Visual mode: double-sided middle textures were not selected when using "Select" action with "with same texture" modifier.
Textures: some optimizations in patch blending code.
ZDoom ACS script configuration: added definitions for StrLeft, StrMid and StrRight functions.
