Remove several dead files (JessicaTegner#394)

* The `md` file appears to be an output file that was mistakenly committed.
  It is not used by the test suite.
* The `test.md` file is unused by the test suite.
* The `test.docx` file is generated by the test suite and can be ignored.

Author: kurtmckee

.gitignore

@@ -5,6 +5,9 @@ dist/
 pypandoc.egg-info/
 .tox/
 
+# Generated by the test suite
+test_data/test.docx
+
 ## IDEs
 # pycharm
 .idea/