Missing documentation entries

[alobbs]

Proper doxygen documentation should be added as comments preceding all public symbols in libhpack.

Statistics on documentation coverage can be generated by running: doc/external/doxy-coverage/doxy-coverage.py build/doc/xml/

As of today, the output is:

100% - /Users/alo/prog/libhpack/libhpack/integer.c - (3 of 3)
100% - /Users/alo/prog/libhpack/libhpack/huffman.c - (2 of 2)
100% - /Users/alo/prog/libhpack/libhpack/integer.h - (2 of 2)
 60% - /Users/alo/prog/libhpack/libhpack/huffman.h - (3 of 5)
     HUFFMAN_DEC_CTX_INIT
     typedef hpack_huffman_decode_t hpack_huffman_decode_table_t[256][16]
 18% - /Users/alo/prog/libhpack/libhpack/header_table.c - (3 of 16)
     BLOCK_PTRS_INCREASE
     hpack_header_block_t static_block
     ret_t hpack_header_block_add
     ret_t hpack_header_block_get
     ret_t hpack_header_block_init
     ret_t hpack_header_block_mrproper
     ret_t hpack_header_block_set_max
     ret_t hpack_header_table_add
     ret_t hpack_header_table_get
     ret_t hpack_header_table_init
     ret_t hpack_header_table_mrproper
     void hpack_header_block_repr
     void hpack_header_table_repr
  0% - /Users/alo/prog/libhpack/libhpack/header_parser.c - (0 of 5)
     ret_t hpack_header_parser_all
     ret_t hpack_header_parser_field
     ret_t hpack_header_parser_init
     ret_t hpack_header_parser_mrproper
     ret_t hpack_header_parser_reg_store
  0% - /Users/alo/prog/libhpack/libhpack/header_store.c - (0 of 6)
     ret_t hpack_header_store_emit
     ret_t hpack_header_store_get_n
     ret_t hpack_header_store_init
     ret_t hpack_header_store_mrproper
     typedef hpack_header_store_entry_t entry_t
     void hpack_header_store_repr
  0% - /Users/alo/prog/libhpack/libhpack/header_field.c - (0 of 5)
     ret_t hpack_header_field_clean
     ret_t hpack_header_field_copy
     ret_t hpack_header_field_init
     ret_t hpack_header_field_mrproper
     ret_t hpack_header_field_repr
  0% - /Users/alo/prog/libhpack/libhpack/header_parser.h - (0 of 5)
     ret_t hpack_header_parser_all
     ret_t hpack_header_parser_field
     ret_t hpack_header_parser_init
     ret_t hpack_header_parser_mrproper
     ret_t hpack_header_parser_reg_store
  0% - /Users/alo/prog/libhpack/libhpack/macros.h - (0 of 4)
     HPACK_ADD_FUNC_FREE
     HPACK_ADD_FUNC_NEW
     HPACK_NEW
     HPACK_NEW_STRUCT
  0% - /Users/alo/prog/libhpack/libhpack/header_field.h - (0 of 7)
     HPACK_HDR_FLD
     HPACK_HDR_FLD_INIT
     ret_t hpack_header_field_clean
     ret_t hpack_header_field_copy
     ret_t hpack_header_field_init
     ret_t hpack_header_field_mrproper
     ret_t hpack_header_field_repr
  0% - /Users/alo/prog/libhpack/libhpack/header_store.h - (0 of 7)
     ret_t hpack_header_store_emit
     ret_t hpack_header_store_get_n
     ret_t hpack_header_store_init
     ret_t hpack_header_store_mrproper
     typedef ret_t(* hpack_header_store_emit_f)(hpack_header_store_t *store, hpack_header_field_t *field)
     typedef struct hpack_header_store hpack_header_store_t
     void hpack_header_store_repr
  0% - /Users/alo/prog/libhpack/libhpack/huffman_tables.h - (0 of 2)
     const hpack_huffman_code_t hpack_huffman[257]
     const hpack_huffman_decode_table_t decode_table
  0% - /Users/alo/prog/libhpack/libhpack/huffman_tables.c - (0 of 2)
     const hpack_huffman_code_t hpack_huffman[257]
     const hpack_huffman_decode_table_t decode_table
  0% - /Users/alo/prog/libhpack/libhpack/header_table.h - (0 of 12)
     HDR_TABLE
     ret_t hpack_header_block_add
     ret_t hpack_header_block_get
     ret_t hpack_header_block_init
     ret_t hpack_header_block_mrproper
     ret_t hpack_header_block_set_max
     ret_t hpack_header_table_add
     ret_t hpack_header_table_get
     ret_t hpack_header_table_init
     ret_t hpack_header_table_mrproper
     void hpack_header_block_repr
     void hpack_header_table_repr