FIX line ranges can vary

fixes #131. I think this what range ought to be doing (fix the lines that are *currently* between a and b).

```
$ autopep8 andy$ cat ~/bla.py
a=12
a=1; b=2;c=3
d=4;

def f(a=1):
	pass

$ autautopep8 ~/bla.py --range 2 2  # before
a=12
a = 1
b=2;c=3
d=4;

def f(a=1):
	pass

$ python autopep8.py ~/bla.py --range 2 2  # after
a=12
a = 1
b = 2
c = 3
d=4;

def f(a=1):
	pass
```

I wasn't sure how to add test case for this...