Merge pull request #349 from jlaura/newstyle_wed

Added W generation
Merge pull request #354 from jlaura/newstyle_wed

Node insertion, precursor to segmentation.
Update README.md
Merge branch 'master' of github.com:pysal/pysal into network
plane sweep for intersection detection
update - need to work on plane sweep for a grid network
Merge branch 'master' of github.com:pysal/pysal into network
testing for planarity
fixing doctest
Merge pull request #428 from sjsrey/network

Merging into network branch.
moving analytics out of wed class and into their own module
Merge pull request #429 from sjsrey/network

moving analytics out of wed class and into their own module
Updated tests, fixed distance segmentation
Merge pull request #430 from jlaura/network

Network