Add -[configureForAutoLayout] for initialized view

This new API method allows you to set translatesAutoresizingMaskIntoConstraints to NO with a chainable method call (as self is returned). It is convenient when you want to use a specific factory method or initializer, and configure the view for use with auto layout on the same line.

For example:
UIButton *button = [[UIButton buttonWithType:UIButtonTypeSystem] configureForAutoLayout];

Closes #75

PureLayout/PureLayout/ALView+PureLayout.h

@@ -45,6 +45,9 @@
 /** Initializes and returns a new view that does not convert the autoresizing mask into constraints. */
 - (instancetype)initForAutoLayout;
 
+/** Configures an existing view to not convert the autoresizing mask into constraints and returns the view. */
+- (instancetype)configureForAutoLayout;
+
 
 #pragma mark Create Constraints Without Installing
 

PureLayout/PureLayout/ALView+PureLayout.m

@@ -61,6 +61,15 @@ - (instancetype)initForAutoLayout
     return self;
 }
 
+/**
+ Configures an existing view to not convert the autoresizing mask into constraints and returns the view.
+ */
+- (instancetype)configureForAutoLayout
+{
+    self.translatesAutoresizingMaskIntoConstraints = NO;
+    return self;
+}
+
 
 #pragma mark Create Constraints Without Installing
 

PureLayout/PureLayoutTests/PureLayoutInstantiationTests.m

@@ -68,4 +68,28 @@ - (void)testInitForAutoLayout
     XCTAssert(view.translatesAutoresizingMaskIntoConstraints == NO, @"The view returned from [[ALImageView alloc] initForAutoLayout] should not translate its autoresizing mask into constraints.");
 }
 
+/**
+ Test the -[configureForAutoLayout] method.
+ */
+- (void)testConfigureForAutoLayout
+{
+    ALView *view = [[ALView alloc] init];
+    XCTAssert(view.translatesAutoresizingMaskIntoConstraints, @"By default, initialized views should translate their autoresizing mask into constraints.");
+    ALView *returnedView = [view configureForAutoLayout];
+    XCTAssert(view == returnedView, @"Calling -[view configureForAutoLayout] should return an identical reference to the same view.");
+    XCTAssert(returnedView.translatesAutoresizingMaskIntoConstraints == NO, @"The view returned from [view configureForAutoLayout] should not translate its autoresizing mask into constraints.");
+
+    view = [[ALLabel alloc] init];
+    XCTAssert(view.translatesAutoresizingMaskIntoConstraints, @"By default, initialized views should translate their autoresizing mask into constraints.");
+    returnedView = [view configureForAutoLayout];
+    XCTAssert(view == returnedView, @"Calling -[view configureForAutoLayout] should return an identical reference to the same view.");
+    XCTAssert(returnedView.translatesAutoresizingMaskIntoConstraints == NO, @"The view returned from [view configureForAutoLayout] should not translate its autoresizing mask into constraints.");
+
+    view = [[ALImageView alloc] init];
+    XCTAssert(view.translatesAutoresizingMaskIntoConstraints, @"By default, initialized views should translate their autoresizing mask into constraints.");
+    returnedView = [view configureForAutoLayout];
+    XCTAssert(view == returnedView, @"Calling -[view configureForAutoLayout] should return an identical reference to the same view.");
+    XCTAssert(returnedView.translatesAutoresizingMaskIntoConstraints == NO, @"The view returned from [view configureForAutoLayout] should not translate its autoresizing mask into constraints.");
+}
+
 @end