Fixed hashbang, replaced with shebang

The hashbang was broken

```python
#/usr/bin/env python
```

So I fixed it and updated it to the new shebang line, introduced in [PEP 397](http://www.python.org/dev/peps/pep-0397/)

```python
#! /usr/bin/python
```

I also added two \n to the message displayed when run with arguments: one at the beginning (so it does not bump against the top of the window), and near the middle, so a word is not split on two lines.

I'm sorry it is saying all these commits want to be merged. I must have updated my fork with the new release incorrectly. It may be best to add the two changed lines (from commit https://github.com/le717/JAM-Extractor/commit/519a0de285f4ed4ca457fef33bd47542d506f501#JAMExtractor.py) yourself and close the PR. :\