Support Python versions 2.6 to 3.0

* Python2.6 requires numbered format specifier {}
* subprocess, check_output is not present in 2.6, use suitable alternative
* shebang line can confuse multi python installation.
* xrange is not supported in python3.
* Fix space and tabs mix in setup.py
Merge pull request #4 from orsenthil/master

Support Python versions 2.6 to 3.0