title: How to do 'git add *' with libgit2sharp?
body: <p>I have an external process that applies changes to files part of a local Git repository initially cloned through libgit2sharp. I would like to perform - through libgit2sharp - the equivalent of the command <code>git add *</code>, followed by <code>git commit -m "Hello World"</code>. The documentation of the <code>Repository</code> class is thin on this. </p>
  
  <p>How can it be done?</p>