Rename insets -> inset and deprecate insets

Source/ConstraintBuilder.swift

@@ -84,6 +84,9 @@ public protocol ConstraintBuilderOffsetable: ConstraintBuilderMultipliable {
     func offset(amount: CGSize) -> ConstraintBuilderMultipliable
     func offset(amount: EdgeInsets) -> ConstraintBuilderMultipliable
     
+    func inset(amount: EdgeInsets) -> ConstraintBuilderMultipliable
+    
+    @availability(*, deprecated=0.10.0, renamed="inset")
     func insets(amount: EdgeInsets) -> ConstraintBuilderMultipliable
 }
 
@@ -420,12 +423,15 @@ final internal class ConstraintBuilder: Constraint, ConstraintBuilderExtendable,
         return self
     }
     
-    // MARK: insets
+    // MARK: inset
     
-    func insets(amount: EdgeInsets) -> ConstraintBuilderMultipliable {
+    func inset(amount: EdgeInsets) -> ConstraintBuilderMultipliable {
         self.constant = EdgeInsets(top: amount.top, left: amount.left, bottom: -amount.bottom, right: -amount.right)
         return self
     }
+    func insets(amount: EdgeInsets) -> ConstraintBuilderMultipliable {
+        return self.inset(amount)
+    }
     
     // MARK: Constraint
     
@@ -764,8 +770,8 @@ private extension NSLayoutAttribute {
             case .Top, .CenterY, .TopMargin, .CenterYWithinMargins, .Baseline, .FirstBaseline: return insets.top
             case .Right, .RightMargin: return insets.right
             case .Bottom, .BottomMargin: return insets.bottom
-            case .Leading, .LeadingMargin: return insets.left
-            case .Trailing, .TrailingMargin: return insets.right
+            case .Leading, .LeadingMargin: return  (Config.interfaceLayoutDirection == .LeftToRight) ? insets.left : -insets.right
+            case .Trailing, .TrailingMargin: return  (Config.interfaceLayoutDirection == .LeftToRight) ? insets.right : -insets.left
             case .Width, .Height, .NotAnAttribute: return CGFloat(0)
             }
             #else
@@ -774,8 +780,8 @@ private extension NSLayoutAttribute {
             case .Top, .CenterY, .Baseline: return insets.top
             case .Right: return insets.right
             case .Bottom: return insets.bottom
-            case .Leading: return insets.left
-            case .Trailing: return insets.right
+                case .Leading, .LeadingMargin: return  (Config.interfaceLayoutDirection == .LeftToRight) ? insets.left : -insets.right
+                case .Trailing, .TrailingMargin: return  (Config.interfaceLayoutDirection == .LeftToRight) ? insets.right : -insets.left
             case .Width, .Height, .NotAnAttribute: return CGFloat(0)
             }
             #endif