title: How to convert Eigen library's Matrix or Vector types to string?
body: <p>How to get text representation for Vector3f or other types in Eigen library. I see lot of examples that uses .format() which returns WithFormat class. This then can be used with cout. However I'm looking for way to get Vector3f as std:string in some human readable form. Exact formatting isn't too important so if Eigen has any default formatting then that works as well.</p>
  
  <p>Note: I can certainly use stringstream to replace cout but I'm hopping there is more direct way to do this.</p>