Update README with circular param details

Author: bachonk

README.md

@@ -32,17 +32,20 @@ Call the following methods on any `UIImageView` instance to set the image:
 
 + `- (void)setImageWithString:(NSString *)string`
 + `- (void)setImageWithString:(NSString *)string color:(UIColor *)color`
++ `- (void)setImageWithString:(NSString *)string color:(UIColor *)color circular:(BOOL)isCircular`
 
 `string` is the string used to generate the initials. This should be a user's full name if available.
 
 `color` is an optional parameter that sets the background color of the image. Pass in `nil` to have a color automatically generated for you.
 
+`isCircular` is a boolean parameter that will automatically clip the image to a circle if enabled.
+
 ##### Example
 
 ```
 NSString *userName = @"Michael Bluth";
 UIImageView *myImgView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 10, 50, 50)];
-[myImgView setImageWithString:userName];
+[myImgView setImageWithString:userName color:nil circular:YES];
 ```
 
 ### Saying Thanks