Merge pull request #1 from deep-introspection/master

Update of kegg-kgml-parser for the last networkx version.
DiGraph: the method .get_node() has changed in the last version of networkx, and it is now called .node
MODULE: added a __init__ empty file, so this script can be imported as a modeul
SETUP: transformed the package to a Python module
SETUP: fixed error of "No module named src"