FIX #149: Stop importing my package on `setup.py`.

* build: Extract version with execfile() on a separate `_version.py` file.
(If i understand correctly what you mean) No, it does not "read lines" but it executes them as python code.  
There is only a single line in `_version.py` that assigns the version-identifier intio `__version__` var, and this is stored into *locals* dict with the name of the var as *key*.