Updated version number to 0.18.1 for release.

Updated version number to 0.18.0 for release.

Updating release notes

Updating ReleaseNotes

Updated version number to 0.17.0 for release.

Updated version number to 0.16.0 for release.

Uppdating release notes for v0.15.1

Updated version number to 0.15.0 for release.

Updated version number to 0.14.0 for release.

Updated version number to 0.13.0 for release.