Merge pull request ishkawa#94 from inamiy/access-level

Change access level of RequestType.parseData() to public.

Merge pull request ishkawa#86 from ishkawa/feature/session

Rename `API` to `Session` and reorganize relationship between `Session` and `NSURLSession`

Merge pull request ishkawa#84 from ishkawa/explicit-null-value

Improve nullable keys handling, restore [String: AnyObject] for `parameters`

Merge pull request ishkawa#83 from inamiy/nullable-parameter-value

Fix parameter type from [String:AnyObject] to [String:AnyObject?] for nullable value.

Update podspec

Merge pull request ishkawa#64 from akisute/master

Added "object" and "URLResponse" to default error, allow users to create more 'rogue' URL path

Merge pull request ishkawa#63 from ishkawa/xcode7-beta6

Updates for Xcode 7 beta 6

Merge pull request ishkawa#60 from ishkawa/feature/fix-url-encoding

Fix parameter encoding in GET request

Merge pull request ishkawa#55 from ishkawa/xcode7-beta4

Updates for Xcode 7 beta 4

Merge pull request ishkawa#49 from ishkawa/swift2

Redesign for Swift 2