title: Make TortoiseHG use my Python installation
body: <p>I created some python hooks for Mercurial that use some external libraries (namely jira-python). In Linux, I install the packages using pip. In Windows, however, Mercurial comes with a bundled version of Python. My hooks fail when I run them because the external packages are not installed. </p>
  
  <p>I want to make Mercurial / TortoiseHG use my Python installation so I can control its environment. How can I do that? </p>