Merge branch 'devel' for 1.9.0 release

v1.8.1 patch release

Merge branch 'devel' for 1.8.0 release

Merge branch 'devel' for 1.7.2 release

Merge branch 'devel' for 1.7.1 release

v1.6.9 release: package.xml, versions, and changelog

Merge branch 'devel' for 1.7.0 release

Merge branch 'devel'

Merge branch 'devel'

Merge branch 'devel'