Use UTF-8 instead of Unicode when saving both .hgignore or .gitignore

Hi,

When using your module I noticed that it doesn't ignore files and folders which were added to the .gitignore file. And with further investigation found that powershell redirect uses Unicode by default for files (see [this](http://www.johndcook.com/blog/2008/08/25/powershell-output-redirection-unicode-or-ascii/)). I changed the code to use UTF-8 instead. What do you think about it?