Move BaseKit Files.

Move the BaseKit project files in to a library folder to help differentiate between what's specific to this library and what's imported in a submodule.

* project/Xcode/BaseKit.xcodeproj/project.pbxproj -> library/project/Xcode/BaseKit.xcodeproj/project.pbxproj
* project/Xcode/BaseKit.xcodeproj/project.xcworkspace/contents.xcworkspacedata -> library/project/Xcode/BaseKit.xcodeproj/project.xcworkspace/contents.xcworkspacedata
* project/Xcode/BaseKit.xcodeproj/xcshareddata/xcschemes/BaseKit (Debug).xcscheme -> library/project/Xcode/BaseKit.xcodeproj/xcshareddata/xcschemes/BaseKit (Debug).xcscheme
* project/Xcode/BaseKit.xcodeproj/xcshareddata/xcschemes/BaseKit (Release).xcscheme -> library/project/Xcode/BaseKit.xcodeproj/xcshareddata/xcschemes/BaseKit (Release).xcscheme
* source/ByteSwap.h -> library/source/ByteSwap.h
* source/Data.h -> library/source/Data.h
* source/Data.cpp -> library/source/Data.cpp
* source/DataReader.h -> library/source/DataReader.h
* source/DataReader.cpp -> library/source/DataReader.cpp
* source/Digest.h -> library/source/Digest.h
* source/Digest.cpp -> library/source/Digest.cpp
* source/SHA1Digest.h -> library/source/SHA1Digest.h
* source/SHA1Digest.cpp -> library/source/SHA1Digest.cpp
* source/BaseKit.h -> library/source/BaseKit.h
* project/Xcode/basekit\_\_osx\_\_framework.xcconfig -> library/project/Xcode/basekit\_\_osx\_\_framework.xcconfig
* project/Xcode/basekit\_\_osx\_\_library.xcconfig -> library/project/Xcode/basekit\_\_osx\_\_library.xcconfig
* source/BaseKit.pch -> library/source/BaseKit.pch
* resources/OS X/BaseKit-Info.plist -> library/resources/OS X/BaseKit-Info.plist