Underscores in generated markdown should be escaped

[dleehr]

The README generated from a completed job lists files, many of which have underscores.

The Markdown rendering (see attached) of this text causes some of it (e.g. middle parts of file names) to be emphasized.

These can be escaped with a preceding \.

$ echo "a_b_c" | markdown
<p>a<em>b</em>c</p>

$ echo "a\_b\_c" | markdown
<p>a_b_c</p>