Re: [PATCH v3 0/6] [GSoC] bitmap: integrate a lookup table extension to the bitmap format

Oops, I forgot to edit the PR cover letter!

I am adding it here. Sorry for that :P

Changes since v2:

 * Log messages related issues are fixed.
 * `pack.writeBitmapLookupTable` is now by default disabled.
 * Documentations are improved.
 * `xor_row` is used instead of `xor_pos` in triplets.
 * In `pack-bitmap-write.c`, `off_t *` is used for `offsets` array
   (Instead of `uint64_t *`).
 * `struct bitmap_lookup_table_triplet` is introduced and functions
   Like `triplet_get_offset()` and `triplet_get_xor_pos()` are removed.
 * `table_size` is getting subtracted from `index_end` irrespective of
   the value of `GIT_TEST_READ_COMMIT_TABLE`.
 * xor stack filling loop will stop iterating if a xor bitmap is already
   stored/parsed.
 * The stack will now store `bitmap_lookup_table_xor_item` items
   Of plain xor_row.
 * bitmap related test files are reformatted to allow repeating of tests
   with bitmap extension enabled.
 * comments are added.

Thanks :)