Initial repository spring clean (#415)

* Move SwipeCellKit & SlackTextViewController to Local Pods directory

* Move playgrounds to own folder

* Create podspec for MMMarkdown and move to Local Pods

Local Pods/SwipeCellKit/SwipeCellKit.podspec

@@ -0,0 +1,16 @@
+Pod::Spec.new do |s|
+   s.name = 'SwipeCellKit'
+   s.version = '1.9.0'
+   s.license = 'MIT'
+
+   s.summary = 'Swipeable UITableViewCell based on the stock Mail.app, implemented in Swift.'
+   s.homepage = 'https://github.com/jerkoch/SwipeCellKit'
+   s.documentation_url = 'http://www.jerkoch.com/SwipeCellKit/'
+   s.social_media_url = 'https://twitter.com/jerkoch'
+   s.author = 'Jeremy Koch'
+
+   s.source = { :git => 'https://github.com/jerkoch/SwipeCellKit.git', :tag => s.version }
+   s.source_files = 'Source/*.swift'
+
+   s.ios.deployment_target = '9.0'
+end