Merge pull request #22 from dexafree/master

Added Preferences Window & Account Upload support
Merge pull request #23 from dexafree/master

Added "Delete screenshot" option && solved bug after deleting
Explicitly unwrap the client id (fixes invalid client id)
Change window title to 'Preferences'
Make the 'Delete screenshot after upload' checkbox only appear on the 'General' tab
Minor Preferences GUI improvements
Align option in the middle
Add open source license header
Change description
Remove pesky .DS_Store
Update to Xcode beta 7
Minor code tidy up, can't wait for Apple to release the official coding conventions for Swift
Update to latest Xcode beta (6.1)
Update to latest Xcode beta (6.1 beta 2)
Code tidied; (some) bugs fixed
Minor code tidy up
Minor code tidy up
Minor code tidy up
Fix crash when response data is nil
Remove unused method