Fix podspec (fix #253)

SDWebImage.podspec

@@ -1,27 +1,28 @@
 Pod::Spec.new do |s|
-  s.name     = 'SDWebImage'
-  s.version  = '3.0'
-  s.platform = :ios
-  s.license  = 'MIT'
-  s.summary  = 'Asynchronous image downloader with cache support with an UIImageView category.'
+  s.name = 'SDWebImage'
+  s.version = '3.0'
+  s.platform = :ios, '5.0'
+  s.license = 'MIT'
+  s.summary = 'Asynchronous image downloader with cache support with an UIImageView category.'
   s.homepage = 'https://github.com/rs/SDWebImage'
-  s.author   = { 'Olivier Poitrey' => 'rs@dailymotion.com' }
-  s.source   = { :git => 'https://github.com/rs/SDWebImage.git' }
+  s.author = { 'Olivier Poitrey' => 'rs@dailymotion.com' }
+  s.source = { :git => 'https://github.com/rs/SDWebImage.git', :tag => '3.0' }
 
-  s.description  = 'This library provides a category for UIImageVIew with support for remote '      \
-                   'images coming from the web. It provides an UIImageView category adding web '    \
-                   'image and cache management to the Cocoa Touch framework, an asynchronous '      \
-                   'image downloader, an asynchronous memory + disk image caching with automatic '  \
-                   'cache expiration handling, a guarantee that the same URL won\'t be downloaded ' \
-                   'several times, a guarantee that bogus URLs won\'t be retried again and again, ' \
-                   'and performances!'
+  s.description = 'This library provides a category for UIImageVIew with support for remote '      \
+                  'images coming from the web. It provides an UIImageView category adding web '    \
+                  'image and cache management to the Cocoa Touch framework, an asynchronous '      \
+                  'image downloader, an asynchronous memory + disk image caching with automatic '  \
+                  'cache expiration handling, a guarantee that the same URL won\'t be downloaded ' \
+                  'several times, a guarantee that bogus URLs won\'t be retried again and again, ' \
+                  'and performances!'
 
+  s.requires_arc = true
   s.source_files = 'SDWebImage/{SD,UI}*.{h,m}'
   s.framework = 'ImageIO'
 
   # TODO currently CocoaPods always tries to install the subspec even if the dependency is on just 'SDWebImage'
-  #s.subspec 'MapKit' do
-    #s.source_files = 'MKAnnotationView+WebCache.*'
-    #s.framework    = 'MapKit'
-  #end
+  s.subspec 'MapKit' do |mk|
+    mk.source_files = 'SDWebImage/MKAnnotationView+WebCache.*'
+    mk.framework = 'MapKit'
+  end
 end