2.1.60: Merge pull request #280 from wbzyl/patch-1

Update progit.asc

2.1.59: Merge pull request #1046 from agowa338/agowa338-patch-1

Update for PowerShell 6 (Core) and Visual Studio Code

2.1.58: Merge pull request #1049 from danstur/fix-1047

Fix incorrect note about PowerShell quoting.

2.1.57: Merge pull request #1048 from pine3ree/patch-1

word typo?

2.1.56: Merge pull request #1045 from jugglinmike/appendix-c-typo

Correct typo

2.1.55: Remove the generation by direct calling of asciidoctor

In order to ensure repeatable book builds and cut down any issues
concerning rendering, the build is only ensured through the
installation of the required versions with bundle and the run of the
Rakefile.

This closes #1039

2.1.54: Remove reference to master for contributors'list

The clone made by travis doesn't seem to get the references.

2.1.53: Merge pull request #1037 from nicktime/patch-1

Fix bzr fastimport plugin install guide

2.1.52: Merge pull request #1038 from notlmn/grammar

add omitted word

2.1.51: Merge pull request #1035 from eyherabh/patch-2

Number consistency