Bundle file format gets extended to allow a partial bundle,
filtered by similar criteria you would give when making a
partial/lazy clone.
* ds/partial-bundles:
clone: fail gracefully when cloning filtered bundle
bundle: unbundle promisor packs
bundle: create filtered bundles
rev-list: move --filter parsing into revision.c
bundle: parse filter capability
list-objects: handle NULL function pointers
MyFirstObjectWalk: update recommended usage
list-objects: consolidate traverse_commit_list[_filtered]
pack-bitmap: drop filter in prepare_bitmap_walk()
pack-objects: use rev.filter when possible
revision: put object filter into struct rev_info
list-objects-filter-options: create copy helper
index-pack: document and test the --promisor option