Add URLs by default
Add URLs by default

According to Issue #152, answers from StackOverflow requires
attribution. This commit provides this attribution in the form
of links.

This commit uses code from https://github.com/gleitz/howdoi/pull/153
as a starting point, but then incorporates the suggestion by GabLeRoux
to use special characters to separate the hyperlink from the answer.

gleitz/howdoi,gleitz/howdoi