Added feedback to Edward's version of gml.write
Added unit tests for gml.write, and updates to gml.write
Merge pull request #8 from enewe101/dev-gml

Added unit tests for gml.write, and updates to gml.write
Commented on latest versions of gml.write(...)
updated per DR comments io/gml.py and tests/gml.py
gml.read() loads node/edge data, loads booleans, negative ints, enquoted ints (for big vals), and escapes xml entities
Merge pull request #10 from enewe101/dev-gml

ml.read() loads node/edge data, loads booleans, negative ints, enquoted ints (for big vals), and escapes xml entities