Support Swift language changes in Xcode 6.1

(Note these changes will not work with Xcode 6.0)

- Added UnicodeScalarLiteralConvertible protocol to JSON
- Added explicit unwrapping where needed e.g. optional NSURL (ideally
we should check for errors first before using the returned objects),
UITableViewCell constructor is now also optional
Make access token properties public, fixes #41
Temporarily remove literal convertible protocol implementations, fixes #51
Fixing compile error

SwifterAuth.swift:69:55: error: value of optional type 'NSURL?' not unwrapped; did you mean to use '!' or '?'?
                NSWorkspace.sharedWorkspace().openURL(queryURL)
Merge pull request #54 from dglancy/beta6-1

Fixing compile error on beta6-1 branch
Add Literal convertible initializeris, fixes #51
Replaced all `id: Int` with `id: String`
Replaced all `id: Int` with `id: String` (found that at least 3 files)
Replaced all `id: Int` with `id: String` (User IDs and Direct Message IDs)

https://blog.twitter.com/2013/64-bit-twitter-user-idpocalypse
Fix postUsersReportSpamWithUserID
Merge pull request #60 from s-aska/armv7

Replaced all `id: Int` with `id: String`
Bug: postDataKey is used without assigning a value
Merge branch 'beta6-1'
Fix iOS demo in 6.1
Redesigned logo
Fix logo width
Remove 6.1 branch note
Fix getStatusesUserTimelineWithUserID not returning specified user's timeline, fixes #57