package kit: Actually add support for B_HPKG_COMPRESSION_NONE

Until now we always declared in the HPKG header that the package file is
zlib compressed. For uncompressed files we would just store all
individual chunks uncompressed. Now we handle completely uncompressed
files slightly differently: We don't write the redundant chunk size
table anymore. The size savings are minor, but it makes the uncompressed
format read-streamable which may be handy.

headers/os/package/hpkg/PackageWriter.h

@@ -52,11 +52,15 @@ public:
 			uint32				Flags() const;
 			void				SetFlags(uint32 flags);
 
+			uint32				Compression() const;
+			void				SetCompression(uint32 compression);
+
 			int32				CompressionLevel() const;
 			void				SetCompressionLevel(int32 compressionLevel);
 
 private:
 			uint32				fFlags;
+			uint32				fCompression;
 			int32				fCompressionLevel;
 };