updated comments

ObjectMapper/Core/Map.swift

@@ -29,6 +29,7 @@
 
 import Foundation
 
+/// MapContext is available for developers who wish to pass information around during the mapping process.
 public protocol MapContext {
 
 }
@@ -72,7 +73,8 @@ public final class Map {
 		// check if a value exists for the current key 
 		// do this pre-check for performance reasons
 		if nested == false {
-			let object = JSONDictionary[key], isNSNull = object is NSNull
+			let object = JSONDictionary[key]
+			let isNSNull = object is NSNull
 			isKeyPresent = isNSNull ? true : object != nil
 			currentValue = isNSNull ? nil : object
 		} else {

ObjectMapper/Core/Mappable.swift

@@ -15,7 +15,7 @@ public protocol Mappable {
 	mutating func mapping(map: Map)
 	/// This is an optional function that can be used to:
 	///		1) provide an existing cached object to be used for mapping
-	///		2) return an object of another class (which conforms to Mappable) to be used for mapping. For instance, you may inspect the JSON to infer the type of object that should be used for mapping
+	///		2) return an object of another class (which conforms to Mappable) to be used for mapping. For instance, you may inspect the JSON to infer the type of object that should be used for any given mapping
 	static func objectForMapping(map: Map) -> Mappable?
 }