Customizable rejection message header and footer decoration

Currently the decoration character and line length are fixed:

========================================================================
                                 REJECTED!
========================================================================
1.1 COMMIT [04c5ad0] on [master] Exactly one issue key must be mentioned in the commit message "Initial import\
========================================================================
                                 REJECTED!
========================================================================

It would be useful if at least the line length was customizable (Eclipse breaks current version to two lines on the UI).