Merge pull request #475 from vobst/prepare_0.9_release

Prepare 0.9 release

Prepare v0.8 release (#440)

prepare v0.7 stable release (#416)

Prepare release of stable version v0.6 (#335)

Fix some intra-documentation links (#197)

Update CHANGES.md

Version v0.3. See Changes.md for details.

Version v0.2. See Changes.md for details

Added CHANGES.md