Changed method name 'get_name()'

from 'get_name()' to 'name()'
Changed method name and field name

modval(), value()
mod_val, modval
Changed some method names

partnum
edgenum
Using izip (itertools) for modularity
Refactor some redundant parts.

partlist,
basic_info,
etc ...
Refactor update_community_structure function.

some redundant part was fixed.
Refactor update_diff in _status.py
Refactor diff calculation in _status.py

minimal diff calculation was also deleted.
Refactor _EdgeStatus class in _status.py

some names of variables and functions.
some variables ware renamed.
Added bipartite synthetic network.
Edge and community updator was separated into two types.

some variables, functions are also refactored.
calculation for diff was improved.
Long rows are shortened.
optimized fue for triparttite network was renamed.
Some exlanetions are added to README.