small changes to allow compiling & running on OS X [tested in Mavericks]

I do not do a lot of C++ or OS X programming so help me improve if there are mistakes. 

I do enjoy Hearthstone and want this logger running on my Mac. With these changes I can build the project via XCode 5 and run the logger. It successfully posts up to hearthlog.com 

HOWEVER I have not yet properly implemented `Helper::GetHearthstoneVersion()` and I need to look around for other methods that needs to be customized for OS X. i just though that in the mean time your users might want this addition. I can supply compiled binaries if desired.