Weighted undirected simple graph added.

Corresponding Testing module not written. Only cython module for edgelist creation & Python module for implementing weighted graph class added.
Missing docstrings added, erroneous ones corrected
Module for edgelist creation of weighted digraph.

Module written in cython. Not yet tested or implemented.
Merge remote-tracking branch 'trunk/master'

Conflicts:
	staticgraph/graph_edgelist.pyx
Modules have been renamed, minor changes
Weighted Digraph class created & module written.

Test module not written yet.
Testing module for weighted graph created.

Bug in edgelist module of wgraph fixed.
Missing docstring added.
Separate array for weights added wrt p_indices

p_weights array is arranged according to the ordering of p_indices
Testing module for weighted digraph added