* Justify API-breaking changes introduced in 4cd9548

* pgm: Handle IOException in Version command
* pgm: Fix missing braces in UploadPack.run()
* pgm: Handle IOException in UploadPack command
* pgm: Handle exceptions in Tag command
* pgm: Fix missing braces in Status.run()
* pgm: Handle exceptions in Status command
* pgm: Fix missing braces in ShowRef.run()
* pgm: Handle IOException in ShowRef command
* pgm: Fix missing braces in Show.run()
* pgm: Handle exceptions in Show command
* pgm: Fix missing braces in Rm command
* pgm: Handle GitAPIException in Rm command
* pgm: Handle exceptions in RevParse command
* pgm: Externalize error message

* JGit v5.2.0.201811281135-m3

* Create FetchRequest superclass with common elements
* Rename Fetch V2 request wantsIds and options
* Move protocol v0/v1 parsing to its own class and request objects

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

* TextBuiltin#init: Factor out a method to get the log output encoding
* ConfigConstants: Add constants for i18n.logOutputEncoding
* Bazel: Increase severity of DefaultCharset to ERROR

* Bazel: Provide toolchain with activated error prone warnings

* Respect "unshallow" lines in protocol v2

* Teach UploadPack "filter" in protocol v2 fetch
* Refactor test of capabilities output
* Refactor v2 advertisement into own function
* Refactor parsing of "filter" into its own method
* Disallow unknown args to "fetch" in protocol v2
* Teach UploadPack shallow fetch in protocol v2
* Refactor unshallowCommits to local variable
* Add protocol v2 support in http
* Give info/refs services more control over response

* RawParseUtils#lineMap: Simplify by using null sentinel internally

* Remove useless for(;;) loop
* Fix DiffFormatter for diffs against working tree with autocrlf=true

* reftable: reserve standard PackExt
* reftable: resolve symbolic references
* reftable: support threshold based compaction
* reftable: compact merged tables
* reftable: merge-join reftables
* reftable: lookup by ObjectId unit tests
* reftable: reflog unit tests
* reftable: namespace unit tests
* reftable: bulk operation unit tests
* reftable: basic functionality unit tests
* reftable: debug tools
* reftable: scan and lookup reftable files
* reftable: create and write reftable files
* reftable: file format documentation

* Remove repository from cache when it's closed
* Fix RefDirectory not closing resources
* Fix repository cache never closing repository

* Fallback exactRef: Do not ignore symrefs to unborn branch
* RefDirectory.exactRef: Do not ignore symrefs to unborn branch

* Improve layout of branches in the commit graph

* Added TestCase for 7d5e1f Fixed RevWalk.isMergedInto()
* Fixed RevWalk.isMergedInto() returning wrong results

* Fix exception on conflicts with recursive merge

* Add close() method to API

* Remove uses of TextBuiltin.out in favor of outw

* EolCanonicalizingInputStream: binary detection should be optional

* Add CleanCommandTest and fix CleanCommand