Added working paused/unpaused game
Implementing Home View Controller and added GameCenter leaderboard/achievements report. HomeVC NOT COMPILING
Updated scene transition to use segues, passed game state using GameMode enum
now defined in GameKitHelper.swift (since it was already imported in both places)
rather than define a new header just for GameMode.
Added game mode label on GameVC to show state passed.
Removed now-unused methods.
Merge pull request #1 from codehearted/homeVC

Updated scene transition to use segues, passed game state using GameMode...
Added home button to game VC; separated classic and timed mode