pep8
init impl attribute test for shp export
ordered attr test for shp import/export
Merge commit 'b32fb6503f62495832def91b0ba7c5a4fda5e7cd'
Fix normalized laplacian when the graph contains selfloops.

When G contains selfloops, the normalized laplacian is defined as NL = D^{-1/2}
(D - A) D^{-1/2}, with A the adjencency matrix and D a diagonal matrix with the
sum of the rows of A in the diagonal. The current NetworkX implementation use D
with the degree of the nodes in the diagonal, which count selfloops twice (this
is the right convension in general, but not the correct one for computing the
normalized laplacian).
Remove from __future__ import.
Add test and fix normalized laplacian for multigraphs.
fix for older versions of GDAL
Merge commit '7fe5c3b63735ba4a9d26936964a74bb9556271e4'
Remove "sci" calls that break embedding in wx. (I don't think they are needed).
Switch from pylab to pyplot.
Close file in decorator tests.

Fixes #746
Adapt ipython's script for testing PR. See ipython/tools
Report missing libraries during tests and number of skipped and passed tests
Add PyPy support. Needs work: In Debian/Ubuntu it is necessary to explicitly add the dist-packages path under /usr/local to import nose
Add unary reverse() operator.
Allow target only specification to shortest_path(_length).
Make nx.reverse() call G.reverse() and use G.reverse() in shortest_path.
Add unary reverse operator to documentation.
Add a try/except clause when checking that the right nx is imported. So we catch the exception if the pull request breaks 'import networkx as nx'
pipe STDERR to STDOUT when installing NX so its output is also written to the log, see #753 .