On the fsfs-format7:  Introduce a framework for space and time-
efficient storage of binary data.  For details, see the header
file documentation.

* subversion/include/private/svn_packed_data.h
  (): new header
  (SVN__PACKED_DATA_BUFFER_SIZE): new constant
  (svn__packed_data_root_t,
   svn__packed_byte_stream_t,
   svn__packed_int_stream_t): new data types
  (svn__packed_data_create_root,
   svn__packed_create_int_stream,
   svn__packed_create_int_substream,
   svn__packed_create_bytes_stream,
   svn__packed_create_bytes_substream,
   svn__packed_data_flush_buffer,
   svn__packed_add_uint,
   svn__packed_add_int,
   svn__packed_add_bytes,
   svn__packed_data_write): declare data write API
  (svn__packed_first_int_stream,
   svn__packed_first_byte_stream,
   svn__packed_next_int_stream,
   svn__packed_next_byte_stream,
   svn__packed_first_int_substream,
   svn__packed_first_byte_substream,
   svn__packed_int_count,
   svn__packed_byte_count,
   svn__packed_data_fill_buffer,
   svn__packed_get_uint,
   svn__packed_get_int,
   svn__packed_get_bytes,
   svn__packed_data_read): declare data read API

* subversion/include/svn_error_codes.h
  (SVN_ERR_CORRUPT_PACKED_DATA): define new error code

* subversion/libsvn_subr/packed_data.c
  (): new source
  (packed_int_private_t): new private data type
  (svn__packed_byte_stream_t,
   svn__packed_data_root_t): define data types
  (create_bytes_stream_body,
   packed_data_create_bytes_substream_body,
   write_packed_uint_body,
   write_packed_uint,
   write_int_stream_structure,
   write_byte_stream_structure,
   write_stream_uint,
   packed_int_stream_length,
   packed_byte_stream_length,
   append_int_stream,
   append_byte_stream,
   write_stream_data,
   read_packed_uint_body,
   read_stream_uint,
   read_packed_uint,
   read_int_stream_structure,
   read_byte_stream_structure,
   read_stream_data,
   unflatten_int_stream,
   unflatten_byte_stream): new utility functions
  (svn__packed_data_create_root,
   svn__packed_create_int_stream,
   svn__packed_create_int_substream,
   svn__packed_create_bytes_stream,
   svn__packed_create_bytes_substream,
   svn__packed_data_flush_buffer,
   svn__packed_add_uint,
   svn__packed_add_int,
   svn__packed_add_bytes,
   svn__packed_data_write): implement data write API
  (svn__packed_first_int_stream,
   svn__packed_first_byte_stream,
   svn__packed_next_int_stream,
   svn__packed_next_byte_stream,
   svn__packed_first_int_substream,
   svn__packed_first_byte_substream,
   svn__packed_int_count,
   svn__packed_byte_count,
   svn__packed_data_fill_buffer,
   svn__packed_get_uint,
   svn__packed_get_int,
   svn__packed_get_bytes,
   svn__packed_data_read): implement data read API

git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-format7@1461865 13f79535-47bb-0310-9956-ffa450edef68