Add podspec

- Closes #20

Gifu.podspec

@@ -0,0 +1,14 @@
+Pod::Spec.new do |s|
+  s.name = "Gifu"
+  s.version = "1.0.0"
+  s.summary = "Highly performant animated GIF support for iOS "
+  s.homepage = "https://github.com/kaishin/gifu"
+  s.social_media_url = "http://twitter.com/kaishin"
+  s.license = { :type => "MIT", :file => "LICENSE" }
+  s.author = { "Reda Lemeden" => "[email protected]" }
+  s.source = { :git => "https://github.com/kaishin/gifu.git", :tag => "v#{s.version}" }
+  s.platform = :ios, "8.0"
+  s.ios.source_files = "Source/**/*.{h,swift}", "Carthage/Checkouts/Runes/Source/Runes.swift"
+  s.requires_arc = true
+  s.ios.deployment_target = "8.0"
+end