scripts/git: Add gitflow configuration

Issue #180.
tools/mkrelease: Don't make a release tag

Issue #180.
tools/mkrelease: Start a new gitflow release

Issue #180.
build/tool: Remove dangling reference to old file

This file no longer exists, so was causing make dist to fail.
build: Add scripts/ to list of SUBDIRS
tools/workflow: Adopt Vincent Driessen branching model

Issue #180.
Merge branch 'feature/180' into develop
Bump release version for '0.1.1'
Merge branch 'release/0.1.1'