Add a tail convenience method that returns a tailing cursor
that implements the recommended way of tailing and reconnecting
in it's iterator implementation.
Also move optional arguments to separate type that can optionally be
added to the various methods.
On some systems the clang include directory cannot be found. This
adds the path detected by bindgen's get_include_dir and a manual
override via an env var.
Thanks to @zerosign for reporting and proposing a solution.
Thijs Cadier