*.py: Remove trailing empty spaces.

Before:

```
file *.py
setup.py:          Python script, ASCII text executable
shapefile.py:      Python script, ASCII text executable, with CRLF line terminators
test_shapefile.py: Python script, ASCII text executable
```

Do the strip:

```
perl -pi -e 's/\s+\n/\n/g' *.py
```

After:

```
file *.py
setup.py:          Python script, ASCII text executable
shapefile.py:      Python script, ASCII text executable
test_shapefile.py: Python script, ASCII text executable
```

Move `shapefile.py` back to dos formatting:

```
unix2dos shapefile.py
```

Author: schwehr