Add tests for edges.
Merge branch 'edges'
Merge pull request #4 from bugamn/master

Fix suggestion for issue #1
Only encode once in remove_node

Addresses #5
Merge pull request #6 from pygraphviz/remove-node-encoding

Only encode once in remove_node
Merge branch 'master' of github.com:pygraphviz/pygraphviz into subgraph
Memory leak fixes for file handling.

Add explicit close to obsolete file handle on read()
Add __enter__ and __exit__ methods so class can be used as a context manager.
Merge pull request #7 from pygraphviz/context-file

Memory leak fixes for file handling.
win32 build fixes:

* uses GVDLL when building for Win32
* avoid creating file handles when not needed. Stops tests from failing on Win32.
* some refactoring - mostly pep8 related
* regenerate using swig 2.0.10
* correct usage of graphviz headers
* Convert "doctest" style tests to nosetests
Merge pull request #8 from mindw/win32_fixes

Win32 fixes
Merge branch 'master' of github.com:pygraphviz/pygraphviz into subgraph

Conflicts:
	pygraphviz/agraph.py