Merge pull request src-d#874 from smola/patchcontext

plumbing: add context to allow cancel on diff/patch computing

Merge pull request src-d#856 from kuba--/fix-840/corrupted-objects

plumbing: packfile, Don't copy empty objects. Fixes src-d#840

Merge pull request src-d#833 from jfontan/slow-reference-update

git: remote, Do not iterate all references on update.

Merge pull request src-d#706 from antham/resolve-commit-sha1

Resolve full commit sha

Merge pull request src-d#803 from TheHipbot/branch-tracking-on-clone

config: adds branches to config for tracking branches against remotes…

Merge pull request src-d#797 from jvusich/fix/oversize-pkt-line

plumbing: format: pktline, Accept oversized pkt-lines up to 65524 bytes

Merge pull request src-d#771 from ilius/PR-log-order

repository.Log: add alternatives for commit traversal order

Merge pull request src-d#749 from irias/master

plumbing: diff, fix crash when a small ending equal-chunk

Merge pull request src-d#720 from jfontan/improvement/cache-delete-mo…

…re-than-one-object

plumbing: cache, modify cache to delete more than one item to free space

Merge pull request src-d#710 from wellsjo/patch-1

fix typo