cleanup: fix typo
CheckRewrite: fix grokking of branch names

The command 'git branch' returns the branch names with a two-character
prefix that we need to get rid of.
Provide for temporary disabling of plugins

If there is an environment variable named after a configured plugin
(githooks.plugin) and its value is false the plugin is disabled.
cleanup: rename $hook to $plugin
refactor: reduce run_hooks complexity
cleanup: make Changes file conform to CPAN::Changes::Spec
todo: improve documentation
Add method Git::More::set_authenticated_user

This method can be used to set the username of the authenticated user
when the default heristics used by the method authenticated_user
aren't enough. The name is cached so that subsequent invokations of
authenticated_user will return it.
todo: collect errors from every hook
Use -a instead of --all in 'git branch' command

Old versions of Git didn't support the long option name.
v0.035