title: VIM: Use python3 interpreter in python-mode
body: <p>I have recently switched to vim and configured it for Python-programming using <a href="http://unlogic.co.uk/2013/02/08/vim-as-a-python-ide/" rel="noreferrer">this</a> tutorial. Before, I have made sure that vim supports python3 (vim --version shows +python/dyn and +python3/dyn) using <a href="https://askubuntu.com/questions/585237/whats-the-easiest-way-to-get-vim-with-python-3-support">this</a> article.</p>
  
  <p>But when executing a file from <a href="https://github.com/klen/python-mode" rel="noreferrer">python-mode</a>, still the python2.7 interpreter is chosen.</p>
  
  <p>How can I configure vim (or the python-mode) to run files on the python3 interpreter?</p>
  
  <p>My OS is Ubuntu 14.04 x64.</p>
  
  <p>Thanks in advance!</p>