A small step towards removing C-style loops

Foundation/NSCFArray.swift

@@ -53,7 +53,7 @@ internal func _CFSwiftArrayGetValueAtIndex(array: AnyObject, _ index: CFIndex) -
 }
 
 internal func _CFSwiftArrayGetValues(array: AnyObject, _ range: CFRange, _ values: UnsafeMutablePointer<Unmanaged<AnyObject>?>) {
-    for var idx = 0; idx < range.length; idx++ {
+    for idx in 0..<range.length {
         let obj = (array as! NSArray).objectAtIndex(idx + range.location)
         values[idx] = Unmanaged.passUnretained(obj)
     }

Foundation/NSCFDictionary.swift

@@ -65,7 +65,7 @@ internal final class _NSCFDictionary : NSMutableDictionary {
             let keys = UnsafeMutablePointer<UnsafePointer<Void>>.alloc(count)            
             CFDictionaryGetKeysAndValues(cf, keys, nil)
 
-            for var idx = 0; idx < count; idx++ {
+            for idx in 0..<count {
                 let key = unsafeBitCast(keys.advancedBy(idx).memory, NSObject.self)
                 keyArray.append(key)
             }

Foundation/NSCFString.swift

@@ -117,7 +117,7 @@ internal func _CFSwiftStringGetBytes(str: AnyObject, range: CFRange, buffer: Uns
     let s = (str as! NSString)._swiftObject.utf8
     let start = s.startIndex
     if buffer != nil {
-        for var idx = 0; idx < range.length; idx++ {
+        for idx in 0..<range.length {
             let c = s[start.advancedBy(idx + range.location)]
             buffer.advancedBy(idx).initialize(c)
         }

Foundation/NSDictionary.swift

@@ -70,7 +70,7 @@ extension Dictionary : _ObjectiveCBridgeable {
 
             CFDictionaryGetKeysAndValues(cf, keys, values)
 
-            for var idx = 0; idx < cnt; idx++ {
+            for idx in 0..<cnt {
                 let key = unsafeBitCast(keys.advancedBy(idx).memory, AnyObject.self)
                 let value = unsafeBitCast(values.advancedBy(idx).memory, AnyObject.self)
                 if let k = key as? Key {
@@ -136,7 +136,7 @@ public class NSDictionary : NSObject, NSCopying, NSMutableCopying, NSSecureCodin
     }
 
     public required init(objects: UnsafePointer<AnyObject>, forKeys keys: UnsafePointer<NSObject>, count cnt: Int) {
-        for var idx = 0; idx < cnt; idx++ {
+        for idx in 0..<cnt {
             let key = keys[idx].copy()
             let value = objects[idx]
             _storage[key as! NSObject] = value
@@ -189,11 +189,11 @@ public class NSDictionary : NSObject, NSCopying, NSMutableCopying, NSSecureCodin
 
     public convenience init(objects: [AnyObject], forKeys keys: [NSObject]) {
         let keyBuffer = UnsafeMutablePointer<NSObject>.alloc(keys.count)
-        for var idx = 0; idx < keys.count; idx++ {
+        for idx in 0..<keys.count {
             keyBuffer[idx] = keys[idx]
         }
         let valueBuffer = UnsafeMutablePointer<AnyObject>.alloc(objects.count)
-        for var idx = 0; idx < objects.count; idx++ {
+        for idx in 0..<objects.count {
             valueBuffer[idx] = objects[idx]
         }
 
@@ -357,7 +357,7 @@ public class NSDictionary : NSObject, NSCopying, NSMutableCopying, NSSecureCodin
         var objects = [AnyObject]()
         getObjects(&objects, andKeys: &keys, count: count)
         var stop = ObjCBool(false)
-        for var idx = 0; idx < count; idx++ {
+        for idx in 0..<count {
             withUnsafeMutablePointer(&stop, { stop in
                 block(keys[idx] as! NSObject, objects[idx], stop)
             })

Foundation/NSSet.swift

@@ -55,7 +55,7 @@ extension Set : _ObjectiveCBridgeable {
 
             CFSetGetValues(cf, objs)
 
-            for var idx = 0; idx < cnt; idx++ {
+            for idx in 0..<cnt {
                 let obj = unsafeBitCast(objs.advancedBy(idx), AnyObject.self)
                 if let o = obj as? Element {
                     set.insert(o)
@@ -176,7 +176,7 @@ extension NSSet {
 
     public convenience init(array: [AnyObject]) {
         let buffer = UnsafeMutablePointer<AnyObject?>.alloc(array.count)
-        for var idx = 0; idx < array.count; idx++ {
+        for idx in 0..<array.count {
             buffer.advancedBy(idx).initialize(array[idx])
         }
         self.init(objects: buffer, count: array.count)

Foundation/NSString.swift

@@ -238,7 +238,7 @@ public class NSString : NSObject, NSCopying, NSMutableCopying, NSSecureCoding, N
 
 extension NSString {
     public func getCharacters(buffer: UnsafeMutablePointer<unichar>, range: NSRange) {
-        for var idx = 0; idx < range.length; idx++ {
+        for idx in 0..<range.length {
             buffer[idx] = characterAtIndex(idx + range.location)
         }
     }
@@ -901,7 +901,7 @@ extension String {
         if characters.count < prefixCharacters.count {
             return false
         }
-        for var idx = 0; idx < prefixCharacters.count; idx++ {
+        for idx in 0..<prefixCharacters.count {
             if characters[start.advancedBy(idx)] != prefixCharacters[prefixStart.advancedBy(idx)] {
                 return false
             }
@@ -918,7 +918,7 @@ extension String {
         if characters.count < suffixCharacters.count {
             return false
         }
-        for var idx = 0; idx < suffixCharacters.count; idx++ {
+        for idx in 0..<suffixCharacters.count {
             let charactersIdx = start.advancedBy(characters.count - idx - 1)
             let suffixIdx = suffixStart.advancedBy(suffixCharacters.count - idx - 1)
             if characters[charactersIdx] != suffixCharacters[suffixIdx] {