Add test case from the issue #2.

I rejected the test_html method, because html2text never actually
promised that the output will be correct Markdown, even less it promised
it will be Markdown formatted according to some particular way.

However, we can try to fix this.
Add bodywidth paramter instead of module-wide BODY_WIDTH.
Travis-CI doesn’t support 2.5 anymore.
Merge pull request #3 from mcepl/avoid_newlines_02

Avoid newlines 02