This can be used as a shortcut to "git checkout feature/full-feature-name".
Feature branch prefix names may be used for convenience.

Only test if local branch is behind origin if origin exists.

They were left behind in the main git-flow script, since they are moved
over to gitflow-common.

new repo is created.

``prefix''. There is no need to install git-flow inside git's libexec dir by
default. It just needs to be *somewhere* on the PATH.

functions, then gitflow-specific functions and finally, assertions to use
in gitflow subcommands.

git specific and git-flow specific functions:

gitflow_current_branch             -> git_current_branch
gitflow_is_branch_merged_into      -> git_is_branch_merged_into
gitflow_local_branch_exists        -> git_local_branch_exists
gitflow_local_branches             -> git_local_branches
gitflow_remote_branches            -> git_remote_branches
gitflow_require_branch             -> require_branch
gitflow_require_branch_absent      -> require_branch_absent
gitflow_require_branches_equal     -> require_branches_equal
gitflow_require_clean_working_tree -> require_clean_working_tree
gitflow_require_git_repo           -> require_git_repo
gitflow_require_git_repo           -> require_git_repo
gitflow_require_initialized        -> require_gitflow_initialized
gitflow_require_initialized        -> require_gitflow_initialized
gitflow_require_local_branch       -> require_local_branch
gitflow_require_remote_branch      -> require_remote_branch
gitflow_require_tag_absent         -> require_tag_absent
gitflow_tag_exists                 -> git_tag_exists
gitflow_test_branches_equal        -> git_compare_branches
gitflow_test_clean_working_tree    -> git_is_clean_working_tree
resolve_nameprefix                 -> gitflow_resolve_nameprefix

GIT_EXEC_PATH overrideable via Makefile command arguments.

that case, don't check if the working tree is clean (this yields errors in
HEADless repos).

This fix enabled users to use "git init && git flow init", too.

variables are all set (they need to be set explicitly once).

fully initialized for use with gitflow.

Add a means of only asking for the missing gitflow definitions, not all.
(Of course, redefining all is always possible using the -f (--force) flag
of init.)

(dash), since the empty string '' means "take the default suggestion"
already. Only needed in rare cases.

conventions, too.