Merge branch 'hotfix/1.22.14' into stable
clarify error message when creating gemset on system ruby, fix #2241
make sure groupadd an be found in standard paths, fix #2242
improve checking for rubinius head version, update #2235
Fixed a few typos in upgrade-notes.txt, closes #2238
1.22.15
Merge branch 'master' into hotfix/1.22.15
Merge branch 'hotfix/1.22.15' into stable
Merge branch 'hotfix/1.22.15'
Detect custom Maven setup on Debian-based systems
Merge pull request #2243 from gildegoma/allow-custom-maven-setup

Detect custom Maven setup on Debian-based systems
make sure certificates are up to date for binary ruby, fix #2244
clean/improve maven and ant requirements, update #2243
fix system name to actually be just one underscore
1.22.16
Merge branch 'master' into hotfix/1.22.16
Merge branch 'hotfix/1.22.16' into stable
Merge branch 'hotfix/1.22.16'
document managing ruby patchlevels with alias
State the expected ruby version and gemset