Merge pull request PowerShell#659 from rjmholt/pses-ipv6-startup-fix

Add @rkeithhill's IPv6 socket fix to PSES startup script

prep for 1.6.0 release (PowerShell#628)

* prep for 1.6.0 release.

* add numbers

Merge pull request PowerShell#578 from PowerShell/rkeithhill/prep-rel…

…ease

Prep for 1.5.1 release.

Bump version to 1.5.0, update CHANGELOG.md

Bump version to 1.4.1, update CHANGELOG.md

Bump version to 1.4.0, update CHANGELOG.md

Bump version to 1.3.2, update CHANGELOG.md

Bump version to 1.3.1, update CHANGELOG.md

Bump version to v1.3.0, update CHANGELOG.md

Bump version to 1.2.1, update CHANGELOG.md