Issue 11 fix w/test

This is simplest fix for #11
I'm not sure about naming convention of tests and version numbering - tell me if something should be changed.

There is a little performance degradation. Measuring 1000 loops with timeit:
1. Before patch: 30.3026938438
2. After patch: 30.9773499966

Measurement code:
```python
import z3c.rml.rml2pdf

def test():
    z3c.rml.rml2pdf.go('src/z3c/rml/tests/input/tag-blockTableStyle-2.rml',
        '/tmp/test.pdf') # (/tmp is a tmpfs)

if __name__ == '__main__':
    import timeit
    print timeit.timeit('test()', setup="from __main__ import test", number=1000)
```