+ boost 1.56.0

bcp function shared_ptr pointer_cast thirdparty/boost
+ libgamecommon 1.0

https://github.com/Malvineous/libgamecommon
+ libgamemusic 1.1

https://github.com/Malvineous/libgamemusic
+ Git ignore list for OS X
* fix compilation errors with Apple's Clang 6.0
+ SDL 1.2.15 main source
+ Xcode project