Preparation for Issue #90 and license checking

This pull request contains a simple script to check that all licenses within the project look the same. I would like to discuss the script and create a external plugin for license / text file header checking afterwards.

All project python source files (including tests, except build.py and check_licenses.py) have the same file encoding comment and license header now.

I created simple tests for the plugins PyFix, PyMetrics, PyLint, Pep8.
Maybe pygments would be worth a try :

```python
from pygments.lexers import guess_lexer
guess_lexer('#!/bin/bash\necho "wtf"\n').name
'Bash'
```

See [stackoverflow](http://stackoverflow.com/questions/325165/is-there-a-library-that-will-detect-the-source-code-language-of-a-block-of-code?answertab=votes#tab-top)

That doesn't solve how we know how to create a comment there but maybe an incomplete approach that only supports python, bash and html (for templates) as a first iteration would be enough.