Change CleanTree action on non-Windows platforms to use forward slashes
C module: Fix clang libtool usage to add the entire file list all the time

Without this, the Mac reports weird architecture changes and the link will
fail.
C module: Add support for Mac OS X 10.9 in C.MacOSX_SDK
C module: Support iOS 7
C module: Fix OS X dsymutil path
C module: Clean the entire .dSYM bundle directory instead of just the Contents folder
C module: Add -arch_only to the libtool flags for OS X
Bootstrapping: Rename lua51.so -> liblua51.so on non-Windows platforms