python-rrdtool as replacement for the upstream Python bindings (#755)

python-rrdtool as replacement for the upstream Python bindings (#755)

* Replaced Python bindings with python-rrdtool

* Updated Makefile.in contents

* Added missing import

* Path correction

* Python 3 compatible print statements in acinclude.m4

* Updated configure script

* Added LIST command to Python binding

* Added missing var decls

* Added callback support for Python binding and initial tests suite for the binding

* Fixed some gcc compiler errors in pre-C99 mode

* setuptools is required to build the Python bindings

* Directory traversal