Added HudPosition class allowing hud elements to be correctly positioned at different resolutions.
Corrected lobby options scroller positioning.
Removed property CustomOption.LobbyTextRowHeight, the scroller now works at every resolution with every text scale.
Added interfaces IToggleOption, INumberOption, IStringOption to allow for external CustomOption derivatives without requiring library modifications.
Added GameplayButton constant values EdgeOffsetX, EdgeOffsetY, OffsetX, OffsetY.
Updated GameplayButton positioning logic to use HudPosition (Vector2 is still accepted by implicit cast).
Renamed event HudUpdate to HudUpdated.
Added events HudCreated, OnHudUpdate, ResolutionChanged.
Added extension Vector2.ToVector3(float z).
Revised more protection modifiers.