Added an initializer with delegate

Since the init method calls the "login" method,
there can be cases where the login completes before
the delegate is set via the property. In this case,
the caller would not know that the login completed

OROpenSubtitleDownloader.h

@@ -38,6 +38,9 @@ typedef enum {
 /// Use a custom user agent
 - (OROpenSubtitleDownloader *)initWithUserAgent:(NSString *)userAgent;
 
+/// Use a custom user agent
+- (OROpenSubtitleDownloader *)initWithUserAgent:(NSString *)userAgent delegate:(id<OROpenSubtitleDownloaderDelegate>) delegate NS_DESIGNATED_INITIALIZER;
+
 /// The object that recieves notifications for new subtitles
 @property (nonatomic, weak) NSObject <OROpenSubtitleDownloaderDelegate> *delegate;
 

OROpenSubtitleDownloader.m

@@ -32,14 +32,19 @@ @implementation OROpenSubtitleDownloader
 #pragma mark Init
 
 - (OROpenSubtitleDownloader *)init {
-    return [self initWithUserAgent:[self generateUserAgent]];
+    return [self initWithUserAgent:[self generateUserAgent] delegate:nil];
 }
 
 - (OROpenSubtitleDownloader *)initWithUserAgent:(NSString *)userAgent {
+    return [self initWithUserAgent:userAgent delegate:nil];
+}
+
+- (OROpenSubtitleDownloader *)initWithUserAgent:(NSString *)userAgent delegate:(id<OROpenSubtitleDownloaderDelegate>) delegate
+{
     self = [super init];
     if (!self) return nil;
 
-
+    _delegate = delegate;
     _userAgent = userAgent;
     _blockResponses = [NSMutableDictionary dictionary];
     _state = OROpenSubtitleStateLoggingIn;