enable more compiler warnings (#252)
enable more compiler warnings (#252)

when a new project is created in Xcode 6, a number of compiler warnings
are enabled by default. this commit changes the project settings so that
the same compiler warnings are enabled for Little Go.

puremourning/littlego,herzbube/littlego,herzbube/littlego,herzbube/littlego,puremourning/littlego,puremourning/littlego,herzbube/littlego,puremourning/littlego,herzbube/littlego