Merge pull request su2code#540 from su2code/release_v6.1.0

Release v6.1.0

Merge branch 'develop' into master

Merge pull request su2code#509 from su2code/release_v6.0.0

Release v6.0.0

Preparing for release.

Small change.

Merge branch 'develop'

Merge branch 'develop'

Merge branch 'develop'

Merge branch 'develop'

Small changes for Windows.