Python 3 support

This pull request fixes #42 (support for python 3.*) . The solution relies on the fact that there is a python2 executable, and it can be found via the "which python2" command.

* Temporarily pointing the python executable to the python2 for ./configure, make, make install. The Node.js build scripts are currently using python 2.*. We should start to advocate for python3 support there, but this may take some time.
* Fixed some inconsistences causing the writefile() function to fail in python 3.*

This solution was tested with success on Ubuntu Linux 13.10, with python 2.7.5 and 3.3.2 preinstalled.
* on python 3 virtualenv created by pyenv-3.3 command and patched with following commands:

        wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py -O - | python
        wget https://raw.github.com/pypa/pip/master/contrib/get-pip.py -O - | python

  (setuptools & pip are included from the 3.4 version AFAIK)
* on python 2 virtualenv created by virtualenv command