Modify edges function
New test code
New test code
Rename libbvg to bvg
	modified:   python-interface/Makefile
	modified:   python-interface/setup.py
	modified:   python-interface/testinterface.py
	modified:   python-interface/testunittest.py
Rename python-interface to python
Rename python-interface to python
Rename python-interface to python
Rename libbvg to bvg
Allow streaming mode when offset step = 1