Add ability to short-circuit the version filters.

An exit of 127 will short-circuit the process.
Output when finishing a branch is wrong.

github: Fixes #102
Fix sanity check for feature track command.

The check for needed branches is incorrect for th command feature track.
This patch introduces a new function: require_local_branch_absent
Update changelog.
Version bump 1.6.0-dev.15
Merge branch 'feature/fix_feature_track_#101' into develop

Fixes: #101
Move most of configuration from ~/.gitflow_export to natural config
Move all configuration from .git/gitflow_config to "--local" conf
The configuration for the base should always be local.

Included the parameter --local to make sure it will only read and write from the local .git config file.
Update Changelog
Version bump 1.6.0-dev.21
Merge branch 'feature/pull_request_#87' into develop
Improve help formatting
Update changelog
Version bump 1.6.0-dev.25
Merge branch 'feature/pr_86' into develop
Initial fork preparations
Update README.mdown