Merge tag '1.7.0' into develop

1.7.0
Preparation for new development cycle after release 1.7.0
Remove redundant test.

The file gitflow-shFlags is always present as we don't use submodules.
Wrong message is displayed upon a rebase
Add rebase command to hotfix
Add rebase command to release
Add rebase command to support
Add rebase shortcut
Update changelog
Extra parameter is not needed
Add new functions for version parameters.
Version bump 1.8.0-dev.11
Merge branch 'feature/add_rebase_command' into develop
Simplify current branch check

Certain commands take either version/name as parameter and if none is given they will use the current branch. The code is over complicated and makes for hard readability of the process.
New function gitflow_use_current_branch_version

Certain commands rely on VERSION. This function sets the VERSION based on the current branch.

Also remove old redundant code.
Version bump 1.8.0-dev.15
Use the base branch when doing a git flow feature diff.

When doing a diff on the feature branch use the base branch which this feature originated from. It will show the committed changes.
Update changelog
Version bump 1.8.0-dev.20
Refactor function "git feature checkout"