* Merge branch 'stable-5.5' into stable-5.6

* [spotbugs] Fix potential NPE in FSTest
* Remove unused import in CreateFileSnapshotBenchmark
* RepositoryCache: don't require HEAD in git repositories
* FileRepository: cleanup refs outside refs/ on reftable conversion

* Do not rely on ArrayIndexOutOfBoundsException to detect end of input

* JGit v5.4.0.201906121030-r

* Merge branch 'stable-4.8' into stable-4.9

* UploadPack: Rewrite setAdvertiseRefsHook to use ternary operator
* UploadPack: Prevent setting null protocolV2Hook
* UploadPack: Add @Nullable annotations

* Merge branch 'stable-4.9' into stable-4.10

* Add API filter for "non-API type FileRepository" in tests

* Minor fixes in three error messages

* Prepare 4.5.3-SNAPSHOT builds

* Update orbit to S20170306214312 (Oxygen M6)

* Silence API error reported in LfsProtocolServlet

* Update .mailmap

* Support atomic push in JGit client

* GroupHead: Remove a redundant call to String.format()

* TestRepository: Allow custom author/committer per-commit
* TestRepository: Use try-with-resources where appropriate

* Handle invalid tree extensions

* Allow configuration of receive pack's ObjectChecker through fsck.*
* Correct fetch to use fetch.fsckObjects and transfer.fsckObjects
* Default receive.fsckObjects to transfer.fsckObjects
* Allow ReceivePack callers to configure their own ObjectChecker
* Check for duplicate names after folding case in ObjectChecker
* Change DirCacheCheckout to verify path using ObjectChecker
* Reject mixed case .git on Mac OS in ObjectChecker
* Reject special Windows device names in ObjectChecker
* Allow an ObjectChecker to reject special characters for Windows
* Reject '.git' as a tree name in ObjectChecker
* Extract path segment check function in ObjectChecker
* Permit ObjectChecker to optionally accept leading '0' in trees

* JGit v3.3.0.201403021825-r

* Move Apache httpclient based HTTP support to a separate bundle

* Fix fast forward rebase with rebase.autostash=true

* Fix patch application WRT windows line endings.

* Add toString() to simplify debugging rebase steps

* Use BatchRefUpdate for tracking refs in FetchProcess
* Batch reference updates together for storage
* Expose ReceiveCommand.updateType to check for UPDATE_NONFASTFORWARD
* Reject non-fast-forwards earlier in BaseReceivePack

* Move NLS test for HttpServerText to http.test

* Add helper for determining if status is clean